A Decision Algorithm That Maybe Related to Quantum Search

Question: As is well known Grover's algorithm can invert a function on a domain of 2^n possible values in other words it can find an x such that f(x)=1 if such an x exists for the oracle f(x). Suppose we are not interested to find the specific value of x but instead want to know if it is true or false if such an x exists and satisfies f(x)=1? What is there a polynomial time and polynomial space quantum algorithm that can decide if such an f exists? The obvious solution is just to use the exponential Grover's algorithm and that can be decided to know if such an x exists-but cam we do better than this?-in other words is there a polynomial time and polynomial space algorithm to decide if it is true or false if such an x exists in the domain? In this question there are not multiple solutions but only one solution if it exists.
Comment: Are you asking us to resolve the question $P=NP$?
Comment: Please consider and review "search versus decision" problems, e.g., [here](https://blog.computationalcomplexity.org/2019/01/search-versus-decision.html). In particular, if we had a way to decide whether one or zero solutions to our oracle exists using, say, $n$ queries, we can do a binary search to find the solution using $n\log n$ queries, by fixing particular qubits and recursing.  Because Grover is optimal for search there's no further advantage for decision.
Comment: @MarkSpinelli I would say that deserves an answer: it answers the question and is quite interesting! At least, I've learned something reading this, so I'd like to upvote it!
Answer: The question appears to ask whether deciding if a problem has a solution could be easier than searching for the specific solution. But, at least for Grover's problem searching is only slightly harder than deciding, because we can do binary recursion at a small cost.
For example if we have a way to decide, in only $O(n^c)$ steps, if there's any $(x_1,\ldots,x_n)$ such that $f(x)=1$ promised that there's either zero or one solutions, we could find the solution in $O(n^c\log n)$ steps by recursively fixing each $x_i$ and deciding if there's a solution with $(0,\ldots,x_n)$; if not, is there a solution with $(1,\ldots,x_n)$; then recurse to fixing $x_2$, etc.  Thus because Grover's algorithm is optimal for unstructured search, it must also be optimal for unstructured decision, and the answer to the OP's question is "no".
This is referred to as the "search to decision reduction" and it's an interesting project to deduce which problems admit such as reduction. Grover's problem does, as does graph isomorphism. As far as I know, however, it's not known whether knottedness admits a search-to-decision reduction.  For example even if we have a fast way to deduce whether a knot is isotopic to the unknot we might not know how to untie the knot.
One other problem unique to quantum computing that might not have such a search-to-decision reduction is the "welded trees" problem of Childs et al. - as explained in this Quanta article. That is, in the welded trees problem we might easily know the vertex label of the EXIT node but we might not have a quick way to know how to traverse the maze to get there.

Although Quanta framed the question as "forgetting" the path from whence the particle came, it's morally equivalent to asking if there's a search-to-decision reduction for their oracle problem.
Answer: In fact, being able to figure out if 1 has a preimage or not is equivalent to distinguishing two oracles: $O_f$ with $O_f|x\rangle|y\rangle=|x\rangle|y\oplus f(x)\rangle$, and $O_0$, where $0$ is the constant function with the value $0$.  (So, $O_0$ is in fact the identity operator $I$.)
Often, the optimality proof of the Grover search is formulated as hardness of distinguishing $O_f$ and $I$, and to be able to distinguish with constant advantage, you need to make $\Omega(\sqrt{2^n})$ queries.  For example, this survey article contains a version of such a proof (Theorem 10).


Percentage/progress Counter on SharePoint List

Question: I have a list in SharePoint that sends an automatic email out to a group of people upon submission. I wanted to explore the possibility of doing a percentage/progress bar indicator that will let people know in the subject line how complete the list item is. For example: There are drop down options that have options of "In folder", "Attached", "n/a", and "Not yet available". If something is "Not yet available" then it would be considered incomplete and the percentage would reflect that. There is a way I could do it with conditional statements and a dozen different email templates, but if the list columns were ever to change, I would need to change it for 10+ email templates and I figured there must be an easier way that I'm missing.
Comment: Could be done with a calculated column which checks for `if not ( == ) then ( = 1) else ( = 0)`. Then you'd still need a `` field to iterate the ``s. This is a clumsy pseudo example utilizing assisting fields. The whole implementation could probably be built with one single calculated column. The update process of such isn't too terrible.
Answer: There is a way you can have the following conditions which require a change in one place if there is a change to your field.

Set workflow variable (status) to Current List Item Dropdown field
Create a workflow variable (temp status) for your email subject
Create a workflow variable (percentage)
The conditions can be as follows

<code>
IF status is "In Folder"
   set workflow variable temp status to "In Progress"
   set workflow variable percentage to "10"
IF status is "Not yet available"
   set workflow variable temp status to "Not Complete"
   set workflow variable percentage to "50"
</code>

Add a email action
Set Subject line. (Add your workflow varibales to subject line)

This approach requires a change at one place where you are setting workflow variable
Let me know if I am missing anything here


What's the significance of the occasional red dot on the Review Queue button?

Question: Occasionally I see a red dot on the Review Queue button (top right). While it seems to work as normal, and doesn't look like there are no more questions / answers than normal to review, I wondered about its meaning? Does it imply review items that have been waiting a while?
Answer: From this answer by a former staff member:

the idea is that when you see the indicator light up, it's a reminder that there are reviews to be done if you haven't looked recently. The goal is to draw reviewers' attention to queues that can use some help.

It also contains details about the implementation specifics.
Comment: Thanks. I hadn't found that older post through search. My search skills severely lacking today. Thresholds make sense.


Windows Azure solr and hadoop data

Question: Is it possible to Index data residing inside the Hadoop storage on azure using SOLR or lucene ?? The data can consists of anything including pdf,doc,docx etc. How can it be achieved?? I am highly confused. Any guidance help is highly appreciated :)
Answer: Disclaimer: I have no experience with Hadoop on Azure.
Basically, you can retrieve each file from HDFS using the following code.
After, you can don anything with this content, for example indexing in Lucene. For this follow the following link

Windows Azure solr and hadoop data


Why do public key systems involve private keys?

Question: I read up the definition of a public key cryptosystem. It mentions there is a public key and a private key. That's confusing. Why is it called a "public key" system if it involves a private key as well?
Comment: This is almost a linguistics question as much as a CS question. Why is a solution of 10% HCl, 90% H₂O called "hydrochloric acid" rather than "water"? When a government has independent legislative and executive branches, why is that called a "presidential system" rather than a "congressional system"? In each case, we name it for the *distinctive* component. All cryptosystems involve keys that need to be secret; what distinguishes public key cryptosystems is that they also have keys that can be public, allowing parties without the secret keys to participate (in specific ways).
Comment: why does this question&answer system involve comments? isn't it a question&answer&comment&review system? Why does computer science involve maths, not just computers?
Answer: Public key cryptography means that the entire communication between both parties is public, including the setup. Contrast this with the case of two parties $A,B$ meeting in secret, agreeing on some keyword, and using this keyword to encrypt future communications.
Clearly, if $A,B$ decide on the encrpyption scheme in public, something has to be kept private (otherwise you could decipher the messages just like the parties involved). This is the private key, so the flow is something along the following lines: $A$ and $B$ publicly discuss and share some information with each other and the world, then they do something in private and send each other encrypted messages. Witnesses to the public exchange alone can't recover what is being said.
The child version of such scheme which I like is the following. Suppose $A$ and $B$ want to agree on some secret color, only known to  them, however the entire exchange must be public. Under the assumption that mixing colors is easy, but given a mixture recovering its components is hard, then they could do the following: $A$ and $B$ each choose a secret (private key) color denoted by $a,b$. Then $A$ sends $B$ the color $c$ (public key), and the mixture $(a,c)$. $B$ now creates the mixture $(b,c)$ and sends it to $A$, and also mixes $(a,b,c)$ and keeps this compound to himself. Finally, $A$ adds $a$ to $(b,c)$ and is now also in the possession of the secret mixture $(a,b,c)$, known to $A,B$ but unknown to anyone who solely witnessed the interaction between them.
Comment: Your first sentence would be better if you replaced "means that … is" with "allows … to be". Public-key cryptography does not _require_ all communication to be public, and in fact some minimal amount of secret communication may be required to achieve stronger security goals (such as verifying that the public keys you receive actually belong to who you think they belong to).
Comment: Can c really be called a public key? (a,c) should be a public key and a should be the corresponding private key. c is a *parameter*. Also this is key exchange, not encryption.
Comment: I like to think of the public key as a safe with an open door and the private key as the key that unlocks that safe. I give you or anyone an open safe. You put your message in that safe and close the door. Now no one, including yourself, can get the message back out aside from myself with my private key. You do the same by giving me a safe and I put my message into it. This way the entire exchange can occur in public yet we can still have secret and secure discussions.
Answer: Security is about protecting yourself from adversaries: it's about achieving something that adversaries can't achieve. Cryptography is a part of security that's about protecting information, to achieve properties such as confidentiality (not letting adversaries know something you didn't intend them to) and integrity (not letting adversaries trick you into believing something you didn't intend to).
It's not surprising that there are cryptosystems that involve secrets. If you want to prevent adversaries from achieving something that's related to information, a pretty obvious way to do it is to know something they don't: you know a secret. A key in a cryptosystem is a fundamental piece of information upon which the security of the system depends. It's natural that a key would need to remain secret: if the adversary knows the key, what can the defender do that the adversary cannot? So it isn't remarkable that a cryptosystem involves a secret key.
It's more surprising that there are cryptosystems involving public keys: keys that the adversary knows. Public keys are still called keys, partly because they are specific to an instance of the cryptosystem and they are pieces of information that make the cryptosystem work, and partly because they do have an associated secret (which is usually called "private key"). Historically, the invention of cryptography involving public keys was a paradigm change. (By the way, the first public-key cryptosystems were not for encryption, but for key exchange: Merkle puzzles and Diffie-Hellman.)
Cryptosystems that don't involve a secret key at all (such as integrity protection through hashes) aren't called "something-key" because they don't involve a key. Cryptosystems that do involve a secret key, but no public key, are sometimes called "secret-key", but usually they're called "symmetric". Cryptosystems that involve both a secret key and an associated public key are called "asymmetric" or "public-key" because the existence of the public key is the remarkable thing about them. (The secret key is usually called "private key" for duality with "public key".)
Comment: I think the last paragraph really answers OP's question: we call it "public key encryption" instead of "private key encryption" because there are other, older kinds of encryption that use private/secret keys _without_ any public keys.
Answer: In a public key cryptosystems, there are operations that everyone in possession of the public key can do, and other operations that only someone possessing the private key can do. For example:

Suppose Alice wants to send a message to Bob. Alice encrypts the message with Bob's public key, which he makes available publicly. Only Bob can decrypt the message, since he is the only one who has access to Bob's private key.

Suppose Alice wants to sign a message. Alice encrypts the message with her private key, which only she has. Anybody can verify the signature by decrypting the encrypted message, using Alice's public key, and checking that it matches the actual message.

In contrast, a symmetric cryptosystem uses the same key for encryption and decryption. To demonstrate how these are used, let us see how one actually implements the two scenarios above:

Suppose Alice wants to send a message to Bob. She chooses a session key at random, and encrypts it using Bob's public key. She then encrypts the message using the session key (and a symmetric cryptosystem). Bob decrypts the session key using his private key, and then decrypts the message using the session key.

Suppose Alice wants to sign a message. Alice computes a cryptographically secure hash of the message (a third kind of a cryptographic primitive), and encrypts it with her private key. Everybody can decrypt the hash using Alice's public key, and check that it indeed corresponds to the message.

A cryptographically secure hash function is a component of many cryptosystems, and it differs both from public key encryption and from symmetric encryption.
Comment: Please don't use signature as encryption with the private key. This is confusing many people,  just use sign a message with the private key. This confusion comes from RSA where we have both signature and encryption. See here [RSA Signing is Not RSA Decryption](https://www.cs.cornell.edu/courses/cs5430/2015sp/notes/rsa_sign_vs_dec.php). Also, for signature we first hash the message as a part of the security ( this also helps to sing long messages, too) since the first true signature; Rabin Signature.
Comment: Real-world cryptosystems based on RSA tend to use different keys for signing and encryption anyway, if only to allow for key revocation.
Answer: Cryptography and particularly ciphers started out using secret key cryptography. This is cryptography where the participants share a secret key. These systems use symmetric ciphers to encrypt / decrypt and Message Authentication Code to sign / verify messages. For example, AES could be used to encrypt / decrypt messages and HMAC to provide integrity / authenticity for them.
The problem with secret (also called symmetric or private) cryptography is that you need to distribute the secret keys. Furthermore, the parties in the scheme cannot authenticate the messages to come from them, as all participants use the same key. These difficulties mean that key management is hard to do.
Enter asymmetric algorithms such as RSA and DH. These algorithms have both a public key and a private key. Basically these algorithms rely on a mathematical problem where you have two keys. These public key performs a complementary operation to that of the private key:

Initial Operation
Key
Complementary Operation
Key

Encrypt
Public Key
Decrypt
Private Key

Sign
Private Key
Verify
Public Key

Key Establishment at party A
Public Key of party B & Private Key of party A
Key Establishment at party B
Public Key of party A & Private Key of party B

The advantage for these schemes is that you can distribute the public keys publicly. This allows for much easier key management, as encrypting a symmetric key with another symmetric key doesn't solve the key management problem; it is just shifted the problem to the next key in line. Do note that the public key does need to be trusted by the participants, otherwise an adversary might just send their own key. For this a Public Key Infrastructure (PKI) is commonly used. For example the certificate store in your browser to support TLS connections is part of a PKI.

Public key cryptography is named after the public key because the public key is what distinguishes secret key cryptography based on symmetric algorithms from public / private key cryptography based on asymmetric algorithms. For cryptography you always need a secret or private key if you want to make messages confidential - using a cipher - or if you want to authenticate messages - using a MAC or signature algorithm. You are right that it would be more precise to call it a public / private key cryptosystem, but humans like to keep it short... language eh?


How to automatically test mobile device and desktop website connections?

Question: We know that Appium can be used to test mobile device applications. We know that Selenium can be used to test PC desktop websites. We want to know how to test the connections between mobile apps and desktop websites? For example, use the mobile app to send a message to a desktop website, how to automatically send the message from mobile and verify that message is correctly shown on a webpage?
Comment: What have you tried so far? What were the results?
Comment: @JoãoFarias we can now only use Appium to control mobile device to send message, but to validate the result from PC website, we have to manually check if the result is correct.
Comment: We now create a script to run Appium test script first, wait some seconds, and then run selenium test script after it to verify.
Answer: In my experience, this form of integration testing is rarely done. I've never seen it. Partly, due to the complicated setup that would be involved.
I do see this as a violation of the F.I.R.S.T principle. Commonly used in unit testing, it can also be extended to other types of testing.

F - Fast
I - Independent
R - Repeatable
S - Self-validating
T - Timely

If you want to test an action on mobile and verify the results on a desktop browser (or vice versa), this would violate "Independence" and "self-validating". You are now having a dependence on multiple devices in order to complete the test and the assertion is not validated on the same device it started on. It would also take a lot of time to setup the right conditions, so in a sense, would not be "timely" to setup.
My recommendation would to not do this and just stick with testing independently on mobile and independently on desktop.
Comment: Thanks for your comment. Seems we can only do this kind of test manually.
Comment: I'm not sure that's what Lee is suggesting;  I think they're advocating for testing each system separately.

If your mobile device tests are able to send messages correctly, and your desktop tests are able to receive messages correctly, then your testing is fine.  Testing both at once leads to bad tests.
Answer: You can always create a Driver Implementation class that initiates and holds both Selenium Webdriver and Appium driver, can make calls to them as per tests demands. Given, that both will work as different processes (browser, mobile emulator/device) there won't be any clashes to trouble the automated testing services you intend to provide.
A sample implementation can be as follows,
Assuming that your testcase is,
Given MyWebApp and MyMobileApp are launched
When I can some message from MyMobileApp
Then I can see the message in MyWebApp
Then, a pseudo code implementation of it can be as follows,
void testCaseMethod(MyDriverImpl myDriverImpl, String message){
myDriverImpl.getWebDriver().get(MyWebAppUrl);
myDriverImpl.getMobileDriver().launchApp();
myDriverImpl.getMobileDriver().findElement(myMobileElementField).sendKeys(message);
myDriverImpl.getMobileDriver().findElement(myMobileElementButton).click();
String recievedText = myDriverImpl.getWebDriver().findElement(myWebElementLabel).getText();
assertEquals(message, recievedText);
}
class MyDriverImpl{
WebDriver webDriver;
AppiumDriver mobileDriver;
DriverImpl(){
webDriver = launchSeleniumWebDriver(); //chrome driver, etc.
mobileDriver = launchAppiumDriver(); //android or ios
}
WebDriver getWebDriver(){
return webDriver;
}
AppiumDriver getMobileDriver(){
return mobileDriver;
}
}


Is the semigroup of nonnegative integer matrices with determinant 1 finitely generated?

Question: The group of $n\times n$ matrices with integer entries and determinant equal to 1, $SL(n,Z)$, is a finitely generated group (in fact, it is generated by 2 matrices). I am interested to know if the semigroup of the matrices in $SL(n,Z)$ where all the entries are nonnegative is also finitely generated. This is true at least in dimension $n=2$.
Comment: As Victor mentioned, the answer is no. A proof can be found here:
http://journals.cambridge.org/action/displayFulltext?type=1&fid=5044204&jid=GMJ&volumeId=15&issueId=01&aid=5044196
Comment: how do you generate SL(n,Z) with only two matrices? It is the case for n = 2, but do you have a reference for higher dimensions?
Comment: The answer is "no" for $n\geq 3$. I've heard Thurston give an elementary proof based on its action on $Z^n_+$ which eludes me at the moment.
Comment: Willie, check this out:
http://hermite.cii.fc.ul.pt/elc/meetings/im_1997/lectures.pdf
See the Theorem by Gow and Tamburini on page 6 of that document.
Comment: The link to `hermite.cii.fc.ul.pt` in a [comment](https://mathoverflow.net/posts/comments/50599) above seems to be broken, but a snapshot is saved on the [Wayback Machine](https://web.archive.org/web/20070611010619/http://hermite.cii.fc.ul.pt/elc/meetings/im_1997/lectures.pdf)
Answer: The question has been amply answered, but perhaps it's worth explaining the geometry of the situation. The positive monoid acts  by projective transformations on the $n-1$-simplex (the view of the positve orthant as seen from the origin, and the partially order on the monoid is the order by inclusion of the image under this action.  In $R^n$, the image of the simplex spanned by the origin together with the basis vectors cannot contain any interior lattice points.  This implies that in the projective action, no proper image can contain its barycenter. This, with its ramifications, gives a strong limitation on images of the entire simplex under the positive monoid.
On the other hand, it's not hard to prove that for $n \ge 3$, the set of images of any face are dense.  In fact, using elementary and well-known theory, there is a positive density of $(n-1)$-tuples of lattice points that extend to a basis for $Z^n$, and any such $n$-tuple of positive elements can be extended to a positive basis.
This implies that there is no finite set of generators, because a single image of the $n-1$-simplex can contain at most simplices near the barycenter over a small range of angles. Here's a picture for the 2-dimensional case:
alt text http://dl.dropbox.com/u/5390048/MatrixSemigroup.jpg
The line segment  is the projection of the pair of lattice points
$L_1=(285, 684, 112)$ and $L_2 = (764, 318, 949)$ found, by pseudorandom selection from lattice cubes that projected near the targeted segment, subject to the condition that they extend to a free basis.
A third element of a basis can be transformed to be project arbitrarily close to any desired point on the line through the image of $L_1$ and $L_2$ by adding $N*L1 + M*L2$, for suitable $N$ and $M$.
Moreover, this characterize the closure (with respect to the Hausdorff topology) of the set of images of the triangle under the positive monoid:  it consists of all triangles spanned by positive free bases, together with set of all line segments contained in the triangle.
Answer: In fact, there are infinitely many "primes" in this monoid $M$, i.e. elements $a$ such that any decomposition $a=bc$ has b or c invertible in $M$ (hence a permutation matrix). Any such prime is necessarily in any generating set (up to permuting lines and columns).
Exercise : if $n=3$, $\begin{pmatrix} 1 & m & m \\\  m & 1+m^2 & 0 \\\ m & 0 & 1+m^2+m^4 \end{pmatrix}$ with $m\geq1$  is an infinite family of (inequivalent) primes.
Comment: I found these example in trying to see if elementary matrices and permutations generate all of $M$. Any element of the submonoid they generate has two comparable columns (and lines), and the above matrices were the first counterexamples I found, of the simple form $C=\begin{pmatrix} 1 & x & x \\ x & a & 0 \\ x & 0 & b \end{pmatrix}$.
The irreducibility follows also, since if $C=AB$, either line $2$ of $A$ contains two $0$, or column $3$ of $B$ does. But this would imply that $C$ is upper block-triangular, hence product of elementaries and permutations (by red. to the $2\times 2$ case).
Comment: correction : This would imply that $A$ or $B$ is upper block-triangular up to permutations, hence a product of elementaries and permutations, and then that $C$ has two comparable lines or columns, which it hasn't.
Comment: Please can you cite where or how you found this?
Comment: @BS, thank you for clarification. I saw your answer just today.(if only you used the "@myname" trick, the comment would have reached me at the right time) I am interested in these matrices and once asked about them here http://mathoverflow.net/questions/26117/prime-undecomposable-matrices. My interest in prime matrices has never dwindled and I would like to know more. Is there a place where one can find more discussion? Thank you.
Answer: See Exercise 28 on my web-site http://www.umpa.ens-lyon.fr/~serre/DPF/exobis.pdf of exercises on matrices. And thanks to BS for having pointed a typo (I wrote $1+m+m^2$ instead of $1+m^2+m^4$).


Testing iOS recurring subscription purchases

Question: Does anyone know how to test subsequent subscription notifications from StoreKit with recurring subscriptions?  I've tested that the first purchase works correctly but I want to test that I'm handling things correctly once the 2nd month's transaction has been generated and sent to my application.
Answer: I found the answer here:
Do auto-renewable subscriptions send an SKPaymentTransactionStatePurchased transaction when they auto-renew?
paymentQueue:updatedTransaction:  will get called with SKPaymentTransactionStateRestored


How can I quickly earn money / experience in Pocket Frogs?

Question: What are some strategies that can be used to quickly earn money or gain experience in Pocket Frogs? For experience, you can complete awards, however it takes a while when your stamp or potion supply runs low.
Answer: One of the easier and less involved ways to make some extra money is to keep two copies of your most expensive frog and then breed them. If you want to make a little extra, keep a habitat with lots of +happiness items and move the frogs into there for a while before you sell. While they're sitting in there getting happier, you can have another set of 8 in egg form. Rinse and repeat.
For more frog breeding tips and tricks, click here
Comment: Dead on, it's the best way to get both money and xp.  Don't forget, different color combinations have different prices, so a little experimentation is necessary.
Comment: This is what I would've answered had you not.
Answer: Here is a way that I found out.

You need to take the two highest level frogs you have and breed them.
Go to Settings -> General -> Date and Time -> Set Date and Time.
Go forward two days or more.
Go back into Pocket Frogs and sell all the frogs. (They should all be matured up.)
Go back to Settings -> General -> Date and Time -> Set Date and Time and go back in time.

You should make a lot of money and experience over time.
Please note that this might affect some of your other games (such as ones where you gain energy or other things over time) in a way where the game counter becomes longer than it should be.
Comment: Thank you I takes a long time but its worth it
Answer: If you breed high level frogs with low level frogs, you get a lot of XP and if you have a lot of potions, you can sell them for lots of money. Lower level frogs supposedly hatch in less time for people who can wait. If you can't wait, I suggest that you download the free pop-up apps to get rare frogs(tribus, glass, chrome, lanterna, etc). You can also race frogs to find chrome or glass frogs(I found both) and if you get 1st place, you can take them and breed for rarer frogs(meaning more money).
Answer: To earn extra money, you need to breed any frogs you can. Then take them to the pond and eat a lot of flies - then the frogs will mature and then make them happy and finally sell them.
Answer: And if you're looking for some free stuff, there is

The daily gift, located on the menu
The frog puzzle game. Every time you finish the puzzle, the frog that you played with will be at full happiness and you get a free item as a prize.
Answer: I have one.
Go to your device settings and change the date to the next day, go to Pocket Frogs, and get the Daily Gift. it won't always be money, but I did it and got a rare frog.

possible after-effects This only works a few times on android. Also, it may cause the game to crash after you've done it quite a few times on apple devices.
Comment: Is there any bad effect once you switch your device back to the real time?
Answer: Doing a race with a frog that has high speed and stamina will get you money if you come in 1st, 2nd, or 3rd. Unfortunately, racing costs money, more money the higher level that you are on. You want to come in 1st or 2nd to get or win back your money. When you race you can also (when you come in first) win an opponents frog... MORE MONEY (when you sell it)!
Answer: Not sure why Ek89005's post was voted down, but it is a decent trick.
Empty your mailbox, then buy the most expensive frog you can (either through catalog or froggiedex - don't worry about "wasting" the money). Once the frog is able to be placed, click "place" then use two fingers to tap two separate habitats at the same time. A frog will appear in each habitat.
BONUS! That expensive frog you'd just placed will still be in your mailbox. You can then do the two-finger-tap repeatedly as many times as you'd like - fill all 15 habitats if you want. Sometimes items will randomly change after a placement. You'll have a ton of green callaina frogs (mostly anura, but some other various ones), "missing" frogs, and flowers. If you have time, scroll through and see what goodies are there. If you want to be quick, just place and sell whatever you want.
Remember your mail box will be screwed up. New gifts will be at the bottom, but deleted if you delete or place something that's listed above it in the mailbox. So, if you get any gifts you want, place those first before doing anything else in the MB.
Comment: @JeffreyLin As a sidenote, we don't mind questions being necro'd.  It doesn't matter how old a post is, so long as the information is good. If not, flag or downvote as needed!
Comment: Hello there necromancer! This question has already been answered, and you are bumping 'dead' questions. If you agree with an answer, gain 15 reputation and then upvote it instead of repeating what was already said.
Answer: So I had the same questions and I used the breeding method with my two extremely rare frogs. It is a fabulous way to get money and experience but if you are impatient and change the time to skip ahead to when the eggs hatch, DO NOT RESET THE TIME AND DATE TO THE CURRENT DATE. If you do this then the game glitches and turns all of the frogs back into eggs. Granted it let me use all of my habitats as nurseries, it's just something to note if you chose that method to earn coins.
Answer: An easy way is to empty your mailbox except for one frog. Also empty your nursery. Next select the frog in your mailbox and click "place" then with 2 fingers tap the nursery. Not only will you get 2 of that frog you will get 255 random frogs in your mailbox. Just sell them all!
Comment: Have you even tested this yourself?


Cannot enable Hyper-V Platform

Question: I am trying to enable Hyper-V in my local machine running Windows 8 Enterprise Ed 64-bit. I checked and my hardware is SLAT-compatible, the option in BIOS is turned on. I did several cold boot but the Hyper-V platform option still remains grayed out. I hope someone can help me since all the blogs/forums that seems to address this issue did not solve the issue for me.
Answer: If you hover your mouse over the Hyper-V item in the Optional Features list, it will tell you why it's disabled.
Otherwise, you can run MSINFO32.EXE and the System Summary panel will list the features required for Hyper-V and whether or not those features have been detected on your system.
Also, you said you've cold-booted the system a few times.  This might sound stupid, but shut your system down and unplug it for a few minutes to make sure it's actually off before plugging it in and turning it on again.  I've never seen a system where I had to do this, but I know other people who have.
Answer: Turn on Data Exeuction Prevention ?
Control panel - System - System Properties -Data Exeuction Prevention

Cannot enable Hyper-V Platform


Open shell TDDFT excitaion contribution

Question: If I have a open shell system (10 alpha electrons and 9 beta electrons) and running TDDFT calculations, is it possible to have a 9a→10b transition? Or does it have to be 9b→10b? Because both exciation won't change the multiplicity of the system, ending with one un paired electrons.
Answer: If by alpha and beta you mean spin up and spin down, you would need spin flip TDDFT.
Standard TDDFT is for the density - density response function $\chi_{\rho\rho}$. It describes the response of the system to a scalar potential $V$ which couples with the density. This captures the effect of an external longitudinal electric field. The density operator is composed by a pair of operators with the same spin, and moreover the spin index is summed. $\rho=\sum_\sigma \rho_\sigma=\sum_\sigma \psi^\dagger_\sigma\psi_\sigma$. This is why you cannot flip spin.
First you need to move to TDSpinDFT. A theory in terms of $\rho_\sigma$ and $V_\sigma$. This captures both a longitudinal electric field and the z component of a magnetic field.
Then you need to generalize this to include the spin flip channel, using $\rho_{\alpha\beta}= \psi^\dagger_\alpha\psi_\beta$. With that you also capture the response to the x and y components of an external magnetic field. This is what can flip the spin.
Comment: Welcome! It is not necessary to post your answer again. For future reference, if you cannot undelete your post, raise a custom flag on it, so moderators can do it for you.

Open shell TDDFT excitaion contribution


Comments/Discussion Not enabled on newly created posts/pages

Question: Like the title says, new posts and pages do not automatically have comments enabled, even though I have the option checked in discussion settings. Any ideas why it may not be working?
Comment: Do you mean that if you create a page, the comments checkbox is turned off, even though discussion settings has them on by default? Or do you mean you have comments turned on but no comment form or comments are shown on the frontend?
Comment: comments checkbox is turned off even though discussion settings has them on by default
Answer: It could be a plugin that is modifying comment settings. First place to look.
Then look at a new post/page. Are comments enabled for that page by default? (On the page/post edit screen, use 'screen options' to ensure that 'comments' checkbox  is enabled, so you see that setting underneath the post content area.)
Do you get the same results when you change to one of the 'twenty' themes?
More info needed, but those are the first places to check, iMHO.
Comment: only plugin i could think of is one that allows me to add categories to pages, all others *shouldn't* affect them. Comments is checked in screen options. Same issue in twenty themes. I do use a self-created theme so I wouldn't be surprised if that *were* the issue, but as I've changed to the twenty-seventeen theme and still seen no issues, I'm inclined to believe that it's a plugin issue, I'll have to go through and manually disable each of them, see if that fixes it.


Why my AMI doesn't have "Createdate" field?

Question: According to http://docs.aws.amazon.com/cli/latest/reference/ec2/describe-images.html and other docs, "aws ec2 describe-images --image-id  ami-XXXX" command should provide AMI creation date as part of the output.
But for all my AMIs (created using "aws ec2 create-image") I receive "None"  instead of creation date.
Any suggestions how to debug it?
Answer: First step would be to upgrade the version of the aws cli you are using, see https://docs.aws.amazon.com/cli/latest/userguide/installing.html
If that doesn't resolve the issue, then you could ask for AWS help at https://forums.aws.amazon.com/forum.jspa?forumID=150 or if you are paying for support, then submit a Support Case.


How I update WordPress theme and plugins

Question: I am using a premium theme and few plugins all are need to update. Previous when I update my theme I lose all of my customization. How can I update my theme and plugins so that plugin and theme customization unchanged.
Comment: Are you using a child theme?
Comment: No. I am not using that. Have any way to update without child theme?
Comment: A decently made theme/plugin will not lose customizations done through their option pages when updated. Only when you have modified the theme/plugin code you lose those adaptations.
Answer: Did your customizations include changing the source code in the theme/plugin files? If yes, then you cannot update without loosing them. Instead you can use the child theme approach. Or you can make a plugin, that makes changes to another plugin or theme, which is harder than just changing the source files and you do not have full control, but then you can update without loosing the changes.
Comment: I didn't modify core file. I just setup slider, post, page, contact page and few others plugins. Actually I don't know how to use child theme. That means all of WordPress users are using child theme to update WordPress?
Comment: @WordpressStudent If you are talking about plugin and theme settings, they are usually stored in the database, so they should be still there after updating. You do not need a child theme for that. It is technically possible to store them in a file that is lost on update, but that would be crazy. If you are loosing settings talk to the theme author or support. It is not normal.


Past Simple and Present Perfect Usage in Daily Life

Question: I have been searching for the differences between these two tenses. I thought I finally understand them but when I watch a movie, the usage of simple past tense is different than I expected. Most of the time, past simple is used without a time expression. I thought that present perfect should be used if time is not given. (unless you are telling a story about the past) For example in this video: https://www.youtube.com/watch?v=GzFWI8KvGmE&ab_channel=linguaclips I would use present perfect instead of simple past. For example: (Instead of saying Where did everyone go? I would say Where has everyone gone? because there is nobody at home)
Comment: As a British English speaker, I too would say "Where has everyone gone?".
Answer: The usage of the present perfect in English is one of the subtlest points in English usage.
Time markers usually suggest using the past rather than the present perfect. Here is a counter example
"I have seen him, just yesterday in fact."
Here the present perfect is giving emphasis.
Recency usually suggests present perfect, and lack of relative recency usually suggests the past, regardless of time markers.
"Julius Caesar has invaded England" has no time marker, but an event some 2100 years in the past requires the past tense.
The fact is that the distinction between the two tenses is very hard to reduce to simple rules.
Answer:
I thought that present perfect should be used if time is not given.

I think that you've got that the wrong way round. If you use present perfect, you should not use a time marker:

I have booked a room on Thursday - incorrect
I booked a room on Thursday - correct

With past simple, you can use a time marker, but it's not required.

I went to see the film on Thursday
I went to see the film that you suggested.

The first sentence reports when something happened. The second sentence affirms that something happened, but does not say when.
According to the British Council, present perfect is used:

for something that started in the past and continues in the present
when we are talking about our experience up to the present

and past simple is used:

for something that happened once in the past
for something that happened several times in the past
for something that was true for some time in the past

Note that there is a difference in usage between British English and American English: Americans often use past simple when they consider an action to be completed, whereas British speakers favour present perfect where the action has a lasting effect.

Where did everyone go? - American English
Where has everyone gone? - British English


life insurance proceeds to creditor

Question: What happens when a beneficiary, who receives life insurance monies in a payout, owes the estate? Can the estate then sue the beneficiary for money owed to the estate? The beneficiary lives in another state, has no money saved or much equity in house, and only money except what will be received through those life insurance policies?
Comment: Can you edit and add country tag.
Comment: Theoretically, if they owe you money you can sue for it, and if you win where they get that money from is mostly irrelevant. We can't tell you what the odds are of your winning; you need to talk to a lawyer about that.
Answer: If a person owes someone money, he can be sued for it, and forced to pay via court order.
It is completely irrelevant who that person owes money to (here: a not specified 'estate'), and irrelevant what source they get money from (here: life insurance payout).
What makes you think there is any special combination that allows the owing person to not pay their debt? If it would exist, everybody would use it to get out of his debt.
Answer: There is no special protection for money obtained from an insurance pay-out.
Answer: A beneficiary will receive the life insurance payment in a lump sum tax free payment.  From there, if that person owes money etc, they could be sued.  But it'll have nothing to do with receiving the life insurance benefit
Answer: The answers above are not quite correct.  There are US states that protect the proceeds of life insurance contracts from certain types of debts in certain circumstances related to the estate and debts of the estate.  This is a local law question.

life insurance proceeds to creditor


How do you find a test location?

Question: I'm new to ham and I'm wondering how to find test locations/study guides. I heard about this from a friend.
Comment: Welcome to ham.stackexchange.com!
Answer: I actually found the website. http://www.arrl.org/find-an-amateur-radio-license-exam-session Thanks.
Answer: You can also use this link https://www.hamradiolicenseexam.com/where-to-take-amateur-radio-exam.htm Hope this was helpful
Comment: Hi Jeyden, and welcome to ham.stackexchange.com!  BTW we recommend not posting just links as answers.  If the linked page contains information, then we recommend summarizing the information in the answer in case the link rots.  When the information is impossible to summarize, like this case, then a little description helps.  Thanks for posting!
Answer: Assuming you are in the US, start with the ARRL License Manual, it costs $32.95 from the ARRL or you can find it at any bookseller. The ARRL, or the American Radio Relay League, is the national association for amateur radio and their web site also has a wealth of information for the aspiring ham, including a search for exam sessions. Also, the FCC recently posted a public notice (PDF) stating that "nothing in the FCC's rules prohibits remote testing" so once you locate a local VE (Volunteer Examiner) you can ask them about whether they offer that if you're concerned about testing in person during the current pandemic. The ARRL has some more information on the topic of remote testing.
The best study guide I have found is the KB6NU No-Nonsense guides; the Technician guide is available as a PDF for free. Technician is the first level of licensing and is also what the ARRL book prepares you for.
These two resources work together, you will want both of them. The License Manual goes in depth into the topics you will need to learn and is essential to get an understanding of all you need to know to not only pass the test but to set up and operate your station safely and effectively. The KB6NU study guide is the refresher you'll want to cram just before the test, as it includes every test question and its answer with just enough context to get the gist, without any of the multiple-choice wrong answers to distract you - but it doesn't explain anything in depth so without having first studied the manual you'll quickly be lost.
Finally, you'll want to take some practice tests. A popular resource is HamStudy.org. The website has flashcards and practice tests along with condensed explanations, similar to KB6NU's guides, and can keep track of your progress as you take the practice tests as many times as you want until you feel comfortable that you can pass the test. They also have an app for $3.99 that lets you do all of that offline.
Good luck! It's a very rewarding hobby and I'm glad you're interested in joining us on the air!
Comment: Your answer covers studying for test, but the question was where to find a location to take the test.
Comment: There were two other answers already with links to find a testing location and I didn't have anything to add to that, so I figured I'd answer the other half of the question, which was study guides.
Comment: @Jim I found some more pertinent info about testing than just the other answers' links, so I added that.

How do you find a test location?


Power analysis using bootstrap -- calculate power

Question: I wish to conduct a power analysis using the bootstrap method to find the difference in means of two groups. I wonder how we can calculate the "power" if we do not know in our data, the null is indeed false. In the book, An introduction to the bootstrap Book by Bradley Efron, the probability of rejecting the null hypothesis at different sample sizes is computed, but this is different from power (which calculates the same quantity conditioned on the Null hypothesis being false). In some papers, I have seen that a constant is added to one of the groups but I am not clear how to choose which group (in a two tailed setting).
Answer: Your concerns are justified - the two samples might come from populations with different mean. To be on the safe side, you can generate two artificial samples by resampling just one of the groups, and add the constant to one of the artificial samples. Do this separately for each of the original groups, and average the power. This should give reasonable results provided your sample sizes are not small.


What is @dynamic in iPad/iPhone

Question: I am jus wondering what is mean by @dynamic in objective-c and how it works.any help please
Answer: @dynamic means that you will provide an implementation of those methods dynamically at run time.
http://developer.apple.com/library/mac/#documentation/Cocoa/Conceptual/ObjCRuntimeGuide/Articles/ocrtDynamicResolution.html
has all the details, but basically using @dynamic means that you promise to provide implementations for the property promised methods at runtime.
In particular look here;
http://developer.apple.com/library/mac/#documentation/Cocoa/Reference/Foundation/Classes/NSObject_Class/Reference/Reference.html
for an example of how you'd construct your dynamic method and place it into the runtime.
Core Data uses this mechanism to provide the accessors. It's quite amazingly cool, once you dig into it :)
And as a side note, meta-programming in ObjC is not for the faint of heart, don't ship it till you grok it, otherwise your users will suffer.
Answer: I am quoting Apple's book The Objective-C Programming Language:

@dynamic
You use the @dynamic keyword to tell
  the compiler that you will fulfill the
  API contract implied by a property
  either by providing method
  implementations directly or at runtime
  using other mechanisms such as dynamic
  loading of code or dynamic method
  resolution. It suppresses the warnings
  that the compiler would otherwise
  generate if it can't find suitable
  implementations. You should use it
  only if you know that the methods will
  be available at runtime.

You can find a pdf copy here.
Answer: Using @dynamic requires that you provide getter/setter methods yourself.
Instead @synthesize creates the getter/setter methods for you.
Comment: Some classes will generate methods automatically, such as NSManagedObject.

What is @dynamic in iPad/iPhone


How Can I Keep EXP Levels, But Not Items?

Question: As of 1.10 You can keep your items with /gamerule keepinventory true. A lot of people say remove EXP, and keep items. However, my goal is to keep EXP, but lose items. Is this at all possible? If it takes a plugin, tell me which one. I can't use mods, as this world is a server. Thanks for noticing!
Answer: Yes. instead of killing a player, you can just clear the items from his inverntory:
/clear [player] [item] [data] [maxCount] [dataTag]

The attributes in brackets are optional. In order to clear every player's inventory, use this:
/clear @a

And to delete 5 dirt blocks from the nearest player's invetory, use this:
/clear @p dirt 5

For more information on how to use the /clear command, visit the Minecraft Wiki
If you want also to teleport the players to spawn, just kill them with /kill @a (assuming you already have done /gamerule keepInventory true)
Comment: @Emeraldimension feel free to hit the gray check mark next to this answer if it helped you! Thanks!


How to stop endermen from taking blocks without cheats

Question: I thought of building a wall to stop mobs from coming in but enderman are frequent annoyances and seem to take pleasure in taking my work apart. How do I stop them without having to disable achievements?
Answer: As on the minecraft wiki,

Endermen can pick up these blocks, if you build your walls out of something not listed here, such as Cobblestone, they can't pick it up. Just remember they are able to teleport into your base through the wall.
Answer:
How do I stop them without having to disable achievements?

Well, your question is tagged as being java edition, which still displays 'advancements' even when cheats are allowed. You could disable mob griefing with the /gamerule command.
Or, if you are on a server, I am pretty sure there is a flag for this in the server software's .yml main config file.


Can Tor work here

Question: I have bitmask vpn always on. How do I then configure orbot to use vpn? Is it possible on android? Tried searching but found nothing that helps me understand. Furthermore is the any special configurations need to run firefox thru tor after. Really could use the help understanding how to configurate all this together.
Thanks for all the help.
Silent Warrior
Answer: If "bitguard" is actually making applications connect over the VPN, then simply starting Orbot would make it connect over the VPN.
To browse with Tor on Android, use the Orfox application which will use Orbot by default.

Can Tor work here


ViewPager or Fragments?

Question: I need to make an application that will basically be a 5 "page" quiz with true and false buttons. I don't think that a new layout/activity is needed for each "page". That would be overkill. Would a fragment or ViewPager be appropriate? Does it break any Android Guidelines? They both seem to make sense to me. Maybe fragments a little more because of a tablet/alternate layout. Any ideas would be appreciated.
Answer: I've been using the ViewPager in one of my projects, for side swiping between similar yet distinctly different views.
It is working very well.
It depends on your flow. View Pager will work well if your users can randomly go through the views. If you want things to be in a specific order then ViewPager probably won't work.
Answer: you can achieved by creating 5 pages dynamically and load that in single layout/activity
By using dynamically load pages helps In  future you want to add 2 pages of question  its easy to do
Answer: According to your flow u can use the this also In same activity you can change the question just on click of button.
And if you want user to revisit all question u can use view pager.

ViewPager or Fragments?


For how many years does a university keep the thesis?

Question: For how many years do universities keep the thesis records. When do they destroy the old thesis reports? If there is some mistake in the thesis then in how many years can the university revoke the degree.
Comment: In many countries, virtually forever. But universities don't revoke degrees for mistakes in the theses.
Comment: Let's be precise - for true mistakes. Plagiarism and related fraud can lead to revocation of a degree (google the Guttenberg, or the Jan Hendrik Schön cases in Germany).
Answer: As far as I am aware, most universities keep a record of PhD thesis awards (title and recipient) in perpetuity. It is also the responsibility of the university library to archive the thesis; which is usually done on a permanent basis.
The reason for this is that future researchers, when doing their literature search should be reading these thesis to understand prior knowledge, as each PhD should be an original contribution to the sum of knowledge. Technology has enabled most universities to eliminate some of the burden associated with the perpetual storage of the thesis documents by allowing the microfilming of the thesis, which has now become the scanning and electronic storage of the work. There are consortia of university libraries that are working to ensure the problem of permanent storage of electronic texts is addressed in an era where we have non archival quality of electronic media.
The answer for the storage of PhD thesis and records would be "forever". For a Master's thesis or dissertation the answer is less clear. In many universities I am familiar with, often only the awarding department archives the Masters, and they are less reliable. I have seen with my own eyes archives of older Masters works being "tidied up". To me it was a travesty, but to others it was modernity.
A degree is not usually revoked on the discover of a "mistake" in a thesis. A degree might be revoked if it was discovered that nothing in a thesis was the original work of the student who submitted it; otherwise known as plagiarism, theft or deceit. It would depend on the statutes and regulations on the awarding institution on whether or how this might happen. One can consult the news archives to find many reported incidents of this happening. The revocation can even happen posthumously!
Comment: @srp: Your fear of your degree being revoked is completely disproportionate. Simple mistakes in your thesis do not endanger your degree. As Brian Tompsett said, only plagiarism and other grave violations are reasons for revoking a degree.
Comment: @srp You should ask this as a separate question. Also, information in [this question](http://academia.stackexchange.com/q/69575/41843) might be useful.
Comment: in my research i was edit some answers for making them significant on the behalf of my adviser. that time i dont know its wrong. but this changes cant effect the anyone because i only change the p value of the result. if i put all results as it is thesis can also be approved. this all happen because of less knowledge of my adviser which i understand after my work experience in teaching. but i insert all experimental data true. if someone complaint in future about my thesis will university revoke my degree and can i defend my degree. i worked on machining of some material.


dead space in a mash tun

Question: My mash tun has a good false bottom, in a stainless steel 15 gallon kettle. The false bottom sits almost two inches above the bottom the kettle.  The maker of the equipment, MoreBeer, says to measure the mash water used from the false bottom. Is this overly diluting the wort? Should the space below the false bottom be less?
Answer: I was going to make this a comment, but it ended up pretty long and there wasn't space...

I think there is often confusion here over just what "dead space" means. Most brew software assumes all liquid under the false bottom is not returned to the kettle, but that isn't always true depending on your equipment.
In my particular setup, I need 1/2 gal of water to fill the space under my false bottom (if I put 1/2 gal of water in my mash tun, then the grains would not get wet), however I also have a dip tube under the false bottom that sucks the wort off the base of the container, so the loss of wort is almost 0. What I do, and I'm not sure if this is "correct" is to enter 0.1 gal of "dead space" or "loss" in my brew software.
Then when I calculate my mash strike water at, say, 1.25 qt/lb, I will then add 0.5 gal to that to account for the space under the false bottom. So for 8 lbs of grain I would strike 3gal of water (1.25qt/lb x 8lb = 10qt, 10qt = 2.5gal, 2.5gal + 0.5gal = 3 gal).
Yes this extra .5 gal would dilute the dissolved sugars, but I've yet to find any real info on if that matters all that much. Since some people will use all the way up to 1.5qt/lb of strike water, I figure my 1.25qt/lb + .5gal wouldn't be much different than just using 1.5qt/lb. I'd venture to guess that doing one thing consistently is more important than hitting the mash thickness according to the numbers from a book.
Answer: You have to take into consideration how much wort is lost to the dead space. That is very important (otherwise you will always end up with less wort than expected in your kettle).
Assuming that you use software or do some calculation, you will enter the loss to the dead space and the calculation will indicate how much water you need in the mash to still achieve the correct amount of wort to the kettle.
The calculation will also show your OG. You may need to increase your amount of base grains to obtain the same OG. This will counter the "dilution".
A safety note: DO NOT TILT YOUR MASHTUN TO GET THE LAST BIT OF WORT OUT! Yes, it sounds like you might be saving a bit of wort, but it is not worth the danger of having hot spent grains splash over you, or the amount of cleaning that you will need to do.
Answer: CodingWithSpike nearly hit the nail on the head: there is no dilution from simply having space under the false bottom.
The important thing is that the outlet (or sometimes a pickup tube) is at the bottom of the mash tun.
When the sweet wort flows out of the grain bed, it is more dense than the water replacing it. Because the smart brewer is not stirring, tilting or otherwise screwing around in the mash, the sweet wort simply follows gravity to the outlet. More dilute wort comes out later, and finally sparge water with just a bit of sugar.
If your mash tun has some big space below the outlet, then you've got a dead space. Your first, sweetest wort will go straight to that spot, and unless you've got a way to stir under the false bottom, it's not going to leave or mix with the thinner wort very much.
If you do have a mash tun with the outlet at the side, you should set it up tilted toward the outlet. You'll probably get better recovery than a flat-bottomed mash tun. Just don't move the thing around while the mash is flowing.

dead space in a mash tun


I dance with nobody & I dance without anybody

Question: I think I dance with nobody and I dance without anybody have the same meaning but are used slightly differently. Is it true?
Comment: Neither *I dance with nobody* nor *I dance without anybody* sound remotely idiomatic to me. Possible alternatives include ***I don't dance with anybody*** (which *might* imply that I *never* dance, no matter who asks me to dance with them) and ***I dance alone*** (which *always* implies that I do dance / am dancing, *without a dancing partner*).
Answer: If you dance with nobody, the implication is that (a bit like Darcy at the ball) you see nobody who you regard as good enough for you.
I dance without anybody implies that you dance by yourself.
So, yes, they don't mean the same thing.
Comment: Could you give a reference for "Darcy at the ball" please. Learners of English are unlikely to be familiar with 19th century English literature. Thanks.
Comment: I know Darcy he in Pride and Prejudice
Comment: @하아아아앙  Indeed he is, a man who had to eat the biggest slice of humble pie in history in order to win over his girl, and didn't regret a crumb of it.


Sharepoint Navigation Link redirects to Home Page

Question: I am facing issues with the Navigation Link from the Navigation where it should redirect to the a different page, but for some reason it redirects to the Home Page, Any help will be appreciated.
Thank you
Answer: I assume the link in the left navigation does not get the right URL. You can edit the destination of the navigation link easily.
Check the detailed steps here:https://support.microsoft.com/en-us/office/customize-the-navigation-on-your-sharepoint-site-3cd61ae7-a9ed-4e1e-bf6d-4655f0bf25ca
Update:
I will upload a simple demo about editing the navigation link:
Comment: Unable to find anything useful in there, Can you help me find that what i should be looking for?
Comment: @TejasThite, I upload a gif about editing the navigation link if it goes to a classical experience.
Comment: Excellent! Thank you, that has helped
Comment: @TejasThite, Glad to be help. Please accept the rely answer if it solves your issue.


Swapping spin operators when commuting

Question: I'm working on a problem at the moment and its asking me to use ehrenfast's theorum to show that my previous answers were correct, but I'm out by a minus sign.
I assumed that if $[S_z, S_x] = ihS_y$, then $[S_x, S_z]$ must be $-ihS_y$.
Is this really stupid?
If I know that $\hat{H} = \omega S_z$, then my expectation value for $S_x$ from Eherenfest's theorem becomes $-\omega \langle S_y \rangle $ right?
For some reason the previous sections sort of requires me to find it as just $\omega \langle S_y \rangle $ but I can't see anything wrong with the way I did my integrals for that part so I'm hoping I've done something something stupid here with Ehrenfast.
EDIT to clarify:
I'm basically just asking if there is any difference between $[S_z, S_x]$ and $[S_x, S_z]$. We know that for spin $[S_z, S_x] = ihS_y$, it's a standard thing. If I swap the operators and commute, is it the same or is it negative?
Comment: You should add more context and details. I really don't understand the question.
Comment: Regarding the edit: Hint:  Check the definition of $[A,B]$.
Answer: Indeed it holds for any two operators A and B: $$[A,B]=AB-BA=-(BA-AB)=-[B,A]$$ You need to provide more details in order to get a more detailed answer to your question.

Swapping spin operators when commuting


Hybrid e-wallets

Question: I am quite confused regarding working of hybrid e-wallets..If private keys are stored on user's browser, then what is the purpose of involving a hosted web service... Can someone please answer my query ?
Comment: What site are you referring to?
Answer: Generally web wallets have you store the keys on your computer, because otherwise they would have control of your Bitcoins and could run off with them.
The reason you need a site is because you can't broadcast transactions to the network without a full node, something that is running on the site's servers.
Web wallets of this type allow you the best of both worlds, you do not need to run software on your computer, and you retain control of your coins as the server never knows your private key.
Comment: Web wallets can generally still steal your coins, even if the keys are stored on your system. They can serve you different javascript that sends the keys back to them once you unlock them to sign a transaction. In fact, this has actually happened in the past. A web wallet trades security for convenience.
Answer: The hosted web service provides a means of accounting over your transactions or can even provide one or more private keys in an m-of-n multisig schema (say 2-of-3) so that neither the web service provider nor you have full ownership over your funds, so if either gets compromised your funds will not be stolen.

Hybrid e-wallets


The 11th term and the 12th term have the same sum as the first 10 terms of the same arithmetic progression.

Question: This question is part of my advanced maths assignment on arithmetic and geometric progressions.
Here's the question:
Q4. Given that both the sum of the first ten terms of an arithmetic progression and the sum of the 11th and 12th terms of the same progression are equal to 60, find the first term and the common difference.
Here's what I've done so far:

 I've done this question about four times and I'm still having the same result.
Comment: Should be $20a+90d=120$, not $20a+45d=120$, I believe you forgot to multiply $45d$ by 2
Comment: You could avoid some of your calculations by dividing $60 = 5(2a + 9d)$ by $5$ to obtain $12 = 2a + 9d$.  Then you have to solve the system of equations \begin{alignat*}{3} 2a & + & 9d & = 12\\ 2a & + & 21d & = 60 \end{alignat*} which is easy to solve for $d$.  Fewer calculations mean fewer opportunities to make an error.
Answer: Here is what I got:
For the first 10 terms and $S_{10}=60$, we have $S_{10}=\frac{10}{2}\left(2u_1+9d)\right)=10u_1+45d$
For the 11th term and 12th term we have $u_{11}+u_{12}=60$ as well. So we have:
$u_{11}=u_1+10d$ and $u_{12}=u_1+11d$ and substituting these values will give:
$60=2u_1+21d$
Now since $10u_1+45d=60$ and $2u_1+21d=60$ as well, we can end up with this equation:
$$10u_1+45d=2u_1+21d$$
$$8u_1=-24d$$
$$u_1=-3d$$
Substituting $u_1=-3d$ to either equations $10u_1+45d=60$ or $2u_1+21d=60$ will still yield same result.
$$2(-3d)+21d=60$$
$$21d-6d=60$$
$$15d=60$$
$$d=4$$
So we have $u_1=-3(4)=-12$
So conclusion:$u_1=-12$ and $d=4$


Connecting Transformer to Ethernet PHY

Question: I have Ethernet PHY from Marvell (88E1111-B2-BAB1I000) and Ethernet transformer (S558-5999-AT-F). By mistake the MDI P&N connection got interchanged on the transformer side. Will it work?
Comment: Does your PHY have the option to flip diff-pair polarity internally?
Answer: The 88E1111 Product Brief (which is the only interesting document I found), says "Automatic polarity correction" in the features. So it seems you're fine. However, they don't mention it later on, so we don't know how it works and if there are restrictions.
Overall, I wouldn't recommend lauching a 10000 production run without having made sure first, but if you are in prototyping phase, it's definitely worth a try. And if your prototype has problems, you can always make a custom RJ45 cable with flipped P/N wires to make it work.
Note it also does auto MDI/MDIX, so you could have flipped the pairs as well (just sayin').

Connecting Transformer to Ethernet PHY


The client asked me to find the figure in the image uploaded to make it as the logo image , what does that mean?

Question: The client asked me to find the figure in the image uploaded to make it as the logo image , what does that mean ???
Comment: Ask your client?
Comment: Seriously, your takeaway here should not be whatever answer scores the best below, but that if you cannot communicate such a simple issue as this with your client then you need to improve your communication skills immediately.
Answer: There is no shame in asking a client to clarify something they've asked you to do. In fact that is really part of your job.
If you don't understand what's being directed, you need to get more information.
Like everyone here, I can guess at what your question means to me however that may or may not be what your client means.
In short....
Ask your client if there's direction you don't understand.
Answer: This is a guess. The client wants to use that robot or game character in his logo and wants you to somehow take it from somewhere.
Only the client knows, is he going to pay for it and has he thought anything about copyright and licensing.
You should tell him:

you can try to find, where it can be copied and who owns the copyright. This work costs XXX/hour (your rate). The price is based solely on used time and it's without any quarantee of useful results.
you can also draw a copy of it, if needed; for ex. because vector version isn't available, it costs YYY
you are NOT going to help to steal it. You make a copy or insert it to something that the client can publish or distribute only after the client gives a signed paper where he assures

he has copyright owner's permission to use it for purpose ZZZ (=exact way to use)
you are hired only to execute physically his usage and
he pays all licensing costs of the usage, you have no part in the licensing

The character is printed in that paper to make clear the subject.
Offer to the client also an alternative - your own creation.


What is the difference between buying the same stock traded on two different exchanges?

Question: Some US ETFs (Vanguard, iShares) that I am interested in are traded on several exchanges, typically including NYS and ASX. I live and pay taxes in Australia. Does is make any difference if I buy the stock on NYS or ASX? Is one of the options better? Taxwise it seems to be the same as I am still subject to 15% witholding tax from dividends paid by the US company in both cases.
Answer: Regarding which exchange to trade your ETFs on, if you trade on the ASX you have to contend with the risks associated with that ETF and its underlying assets. If you trade on the NYSE you will have to contend with these same risks with the addition of Currency or Foreign Exchange risk (the change in the AUD:USD when you buy and when you sell).


The spell temper (old card) effect in combat damage resolution

Question: Temper prevents the next 'X' damage and puts 'X' +1/+1 counters on a creature.  Do those counters increase the damage done by this creature in the combat resolution step?
Also how does it interact with an 'Nomads en-Kor' style damage redirection or a Boros Reckoner?
Answer: Okay there's two questions here so lets take them one at a time. First though being combat damage only matters for the timing of the damage in the first question, Temper works the same way regardless of how the damage is dealt.
1) Temper will NOT change the damage done by that creature in the same damage step, damage is already assigned in full, and would have been dealt at the same time it was to take the damage being prevented. Making a creature more powerful after damage is assigned doesn't change that. If however the damage prevented was from a first strike source, and your creature does not have first strike, or has double strike, the second damage step will have those counters and will do that extra damage. This is seen more recently with the effect of Drana, Liberator of Malakir every time she hits all attacking creatures get a +1/+1 counter, and she has first strike.
2) If Temper was placed on Boros Reckoner, his effect will not be triggered, he was dealt no damage so his effect does nothing. The en-Kor redirection effects could go either way, assuming one player controls both the effects that player chooses which one applies first and which tries to apply second. The one that would apply second fails to happen, because damage is no longer going to be dealt to that creature. This is covered in the Comprehensive rules:

616.1 If two or more replacement and/or prevention effects are attempting to modify the way an event affects an object or player, the affected object's controller (or its owner if it has no controller) or the affected player chooses one to apply, following the steps listed below. If two or more players have to make these choices at the same time, choices are made in APNAP order (see rule 101.4).

If Temper is cast on the creature that damage is being redirected to, both effects will apply, the damage will be redirected and then prevented.
It's worth noting that Temper still prevents X damage during that turn, unlike some other sources it does not care from where or when the damage is dealt, beyond that it is all in that one turn. So if you redirect all damage from a group of en-Kor creatures being hit by something like pyroclasm it will prevent all of up to X of that damage, and if anything is left be able to prevent still more later in the turn.
Comment: You might want to clarify why Temper can prevent more than 1 point of damage if cast on the creature that en-Kor redirected to.
Comment: @Taemyr Fair enough, I added in that number of sources doesn't matter, though that part should be obvious. More important was to fix that they have an option on the en-Kor/replacement effects.
Comment: I haven't played MtG in ages, so on reading en-Kor thought that you could only prevent one damage.  Then read your answer and rethought, because I would have no problem with Temper preventing damage from multiple completely different sources - then I tried to find the rules that applies, but struggle a bit with that because prevention effects is a continous effect; so how long does a continous effect from an instant last?  All in all I think I am beyond the scope of the question though.
Comment: @Taemyr you can activate the ability as many times as you can afford, and since the en-Kor effect has a cost of 0, that's infinite. It just redirect the first point with the first one, then the next point is the first one again and it gets redirected also.
Comment: @Taemyr as for how long it lasts, the oracle text for Temper says "
Prevent the next X damage that would be dealt to target creature this turn. For each 1 damage prevented this way, put a +1/+1 counter on that creature." IT lasts to the end of the turn.
Comment: Yes, the oracle text is way clearer. - IIUC, without the oracle text the effect would remain until the spell had prevented the full X amount, even across subsequent turns.  (By 611.2a)


Using 4096*4096 background image in uinty tk2d

Question: I am new to Unity and I am developing a game using unity its a 2d game i am using tk2d framework. I have a big background image(4096*4096) how can I load this background so only visible part of the background has to be rendered so it wont effect the performance. How can I achive this in unity & tk2d?
Comment: there is something called mega textures - i believe games like Rage use them - also 'The other brothers' - www.tobgame.com makes use of painted backgrounds (in unity) for their entire levels instead of tile based systems - so it is possible but may require more research
Comment: "Megatextures" is just marketing IMO. Behind the scenes there are still classic hardware limits and the bigger your textures get, the higher the costs (memory, handling times, etc.). Most of these "Megatextures" implementations simply handle all the mapping and usage while staying within the hardware's specific capabilities. Overall it's something I'd avoid on mobile platforms at all costs. Even if you've got free ressources you should probably better utilize them for something more important or leave them to save battery power.
Answer: You're going to have to break up the image into multiple sections.  Probably 1024x1024 for maximum compatibility (source).  Then you can just place them in the  background in order.
Comment: After breaking down into 1024x1024, can i use just 8 sprites or is there any other class already exists for doing this kind of job.


Each time I reboot Ubuntu 12.4 in my vmware on Mac OS the share folder are not mounted

Question: I installed the VMwareTools-8.8.4. The shared folder was working fine. Each time I reboot Ubuntu 12.4 in my vmware on Mac OS the share folder are not mounted? Any idea of what is happening?
Answer: So, MAC is the host and Ubuntu is the client.
It's the default behaviour, the VMware shared folders are basically folder shared over the network and without modifying fstab they are being mounted only when you need them.
You can follow this steps How do I mount shared folders in Ubuntu using VMware tools?


Substitution for green meat radish

Question: A recipe I'm following asks for a green meat radish. Where would be a good place to get one (I'm from the UK) or what could I substitute it with?
Comment: I can't post this as an answer, as I've never tasted green meat radish [also being from the UK] but Asda sell mooli/daikon these days, so that might be a relatively easy to obtain substitute. [repost due to typo]
Comment: what recipe is this ? can you share it ?  I would imagine you can you regular red or pink radishes.
Answer: I'm in the US and I had never heard of a green meat radish. However, based on information I found on Specialty Produce, I would think you could substitute almost any regular variety of radish you find at your local grocer.
Excerpts from the linked page:

Description/Taste
Green Meat radishes are easily distinguished by their shape and color. The swollen and elongated taproot is two-toned like several radish varieties, yet it is unique in its coloring. Its upper half near the stem end is lime green colored, and its tapered lower half is cream colored. It can be harvested when as small as five inches or as large as ten inches. Its thick skin covers a green to creamy white flesh which offers a crisp texture and a radish flavor that can vary from mild to hot depending upon growing conditions and maturity.

and

Applications
The spicy flavor and crisp texture of the Green Meat radish shines in fresh preparations. Slice thin and add to sandwiches, salads or wraps. Use to add a spicy accent to tacos, nachos, and Mexican soups. Slice lengthwise and pair with cream based dips or soft cheeses. Grate and serve as a condiment with sushi or sashimi or add to slaws to give them a spicy kick. In China Green Meat radishes are popularly pickled along with Sichuan peppers. Green Meat radish greens can be added to soups and stir-fries. To store, keep Green Meat radishes refrigerated and used within one to two weeks.

More interesting reading on the linked page, also.
Answer: Seeds are available in the UK if you want to grow your own, though that's only good if you want to wait a few months (my usual supplier of veg seed, Chiltern, doesn't have them).
From descriptions I've read, they're closer to the milder pink summer radishes in flavour than to the winter radishes (like mooli).  So you're probably best just using normal radishes, toning down the quantity if you're worried about the overall effect being too peppery.
Answer: Try a specialty Asian food market, which you should be able to find in the closest metropolitan area to you. It is a similar to daikon, and that can be substituted with turnips or white radishes (for texture) and a small amount of horseradish (for spice).

Substitution for green meat radish


Mounting a disk image split up into two files

Question: If I had a four gigabyte disk image, and I copied the first, say, two gigs, into a file at one path, and the remaining two gigs into a file at a different path, could I mount it as one disk image on one mount point despite half being in one file and the other half being in another file? Or if that's not possible if I had one disk image with one, say, ext4 partition and another with the same partition table and ext4 partition, would I be able to mount them on the same mount point? Methods that require FUSE will work for me.
Answer: It is theoretically possible to make such a FS, but I doubt it already exists or has any real potential with the constant increase of drive size and the huge file size support on all modern systems.
One way that you could split your partition in two would be to set up a RAID 0 array (using mdadm) with the two separate files (on loop devices) and then copy the initial 4GB partition image to the new split partition.  For simplicity, make sure that the resulting size is exactly the same as your initial partition.
Answer: You can mount two filesystems on a single mount point and there are actually a few ways of doing this and almost all live CD distros use them.  But first you have to decide how you want to handle writes. If you need both filesystems to be merged and appear as one with all the files from both systems available but the writes going to only one of the filesystems then you can use overlayfs   https://en.m.wikipedia.org/wiki/OverlayFS, unionfs or aufs
If however you need all of the filesystems to be read-write enabled you can have a look at mhddfs http://svn.uvw.ru/mhddfs/trunk/README


How many vertices per second can the average graphics card push?

Question: How many vertices can your run of the mill $100 gfx card push these days?
Comment: It's not about quantity, it's about quality. Would Super Mario 64 be a better game if it had 10 times the number of vertices in it? No, not really. The player rarely notices the graphical quality when playing, it's only the onlookers that really benefit. It's not like you're sitting there with a sniper rifle and think "ooh, look at the detail on that crate."
Comment: If you're new to games programming, and you're doing it in your own time, then it would be quite hard for you to push your average graphics card to it's limit without doing something horribly wrong. To push the limits you usually need lots of high detail meshes with lots of high detail textures with lots of custom shaders and usually these aren't cheap.
Comment: Unfortunately once migrated a question cannot be migrated back without some serious changes by the team. However the OP can register on SU and associate his account to gain edit ability to this question. Email firstname.lastname@example.com should you have any queries on this.
Answer: This isn't a very interesting number. Mainly because on modern graphic cards vertex and pixel shaders share the same computational hardware. So with rendering the theoretical maximum of vertices you aren't able to draw a single pixel.
Answer: The Geforce 6600 can do 375 million vertices per second, and it has a street price of substantially less than $100.  The Geforce 9800 retails for about $100, but at that level they don't seem to use Vertices Per Second as a measurement anymore.
Answer: What exactly would vertices per second measure? You leave out too many variables.
What would you use the metric for? As a sane default or upper bound for your application's draw calls? For benchmarking? If so, you probably want to benchmark fill rate and triangle draw rate instead. See my post regarding this here: https://stackoverflow.com/questions/1493581/how-to-go-about-benchmarking-a-software-rasterizer/1504635#1504635
On the other hand, if I take your question literally, I sadly don't know of any trustable sources for low-end graphics hardware performance. You surely don't want to trust the vendors themselves. I know of a good usage survey though, and that's the monthly Steam hardware survey: http://store.steampowered.com/hwsurvey/
Since I'm not aware of any sites with good and deterministic benchmarks statistics, knowing which cards (and technology) is popular is the second best thing, if you need some statistics to help you make correct choices for your target group.
Answer: Further to Sebastian's comment bear in mind that due to shader hardware the number of vertex transformations is largely irrelevant.  What constitutes a transform?  You can bet they just do a simple matrix multiplication to a position only vertex (I know Microsoft and Sony did that for their X-Box and PS2 vertices-per-second marketing bumph).
In this day and age the most meaningful things are memory bandwidth and shader cycles per clock.  Of course driver are free to re-order instructions to improve throughput.  Lots of latencies can be hidden this way which makes the hardware produce faster results.


Is it possible to determine the UI panel class that is parent/host to an operator when its button is clicked?

Question: I'm dynamically registering a variable number of panel classes, all sub-classed from a custom panel class that includes an operator. Thus all the new panel sub-classes contain a button that executes this common, ancestral operator code. When the button on one of these new sub-class panels is clicked I would like the operator code to be able to determine which of the panel/button instances invoked it. Is such a thing possible? My apologies if I've not described this very clearly. Basically I'm trying to recreate the same functionality as the 'X' button that sits in the header of modifiers sub-panels. In my example, the code behind the X button needs to know which panel class the clicked button belongs to in order to unregister the correct panel. Any advice is greatly welcomed and appreciated. Thank you!
Comment: Suggest you could do this by setting a context pointer in layout  to the class to unregister. eg https://blender.stackexchange.com/a/203443/15543  `row.context_pointer_set(name="foo", data=self.__class__)`
Comment: @batFINGER Thanks! Per the idea from lemon, I just got this working by storing the panel class bl_idname in an operator variable when the panel is registered, then later using that to unregister the panel. That works but it still feels a little imperfect, a pointer would be much cleaner. I'll try your suggestion later, thank you again for taking the time to answer.
Answer: You can define a property for the operator in order to identify something.
For instance:
class SimpleOperator(bpy.types.Operator):
    """Tooltip"""
    bl_idname = "object.simple_operator"
    bl_label = "Simple Object Operator"

    # >>>> Declare a property
    some_value = IntProperty(default=0)

    @classmethod
    def poll(cls, context):
        return context.active_object is not None

    def execute(self, context):
        print(self.some_value)
        return {'FINISHED'}

Then, in the panel you can assign the property value as you want:
class HelloWorldPanel(bpy.types.Panel):
    """Creates a Panel in the Object properties window"""
    bl_label = "Hello World Panel"
    bl_idname = "OBJECT_PT_hello"
    bl_space_type = 'PROPERTIES'
    bl_region_type = 'WINDOW'
    bl_context = "object"

    def draw(self, context):
        layout = self.layout

        row = layout.row()
        op = row.operator("object.simple_operator")
        # >>>> Assign its value
        op.some_value = 1
        op = row.operator("object.simple_operator")
        # >>>> Assign its value
        op.some_value = 2

Alternatively, you can assign the value in a subclass if your want to work with subclasses.
Comment: That's perfect, thank you! And what a resounding forehead slap! I knew I was making it more complicated than it needed to be. Much appreciated!


Why is it recommended to make the cone of vision 60 degrees?

Question: Im currently trying to understand the cone of vision and I was wondering why the cone of vision is recommended to have 60 degrees? I mean where does the number come from? I always though the vision span was about 120 degrees for our eyes?
Answer: The problem isn't in our eyes. Its a geometric problem when 3D shapes are drawn on 2D paper having perspective.
If one draws objects with perfect perspective, they start to be increasingly distorted and look out not plausible if they are more than 30 degrees off from the midpoint of our field of sight. That makes the 60 degrees wide cone to be the area for shapes that can be drawn with exact perspective and the result also looks out plausible.
Of course there's no strict limit. The 60 degrees limit is based on experience. It's only a thumb rule. A mathematician probably could find a good measure for the apparent distortion of perfectly in perspective drawn shapes and would show that about 60 degrees width is some kind of well definable culmination point of the apparent distortion. But this is beyond the scope of my answer.
Here the phenomena is explained simply without math:
https://courses.byui.edu/art110_new/art110/week02/cone_of_vision.html
Comment: also worth pointing out that with **no eye motion**, human cone of vision is around 60° - the reason we have a 120° span is partially because we constantly shift our eye positions and head position, and our brain is *extremely* effective at stitching the resulting images into an experienced 120° panorama.


When planting is it good to use one pot for each plant or one large common pot?

Question: I'm trying to plant some vegetables in my second floor balcony. I have one container for each plant. Is this the best method or should I go for one long common container to plant all of them? What are the advantages and disadvantages?
Comment: What you intend to grow has a lot of say.
Answer: Overall, I think separate containers is an advantage over a common container in your case: a light hobbyist grower.
I can think of 3 advantages to a common container for you:

Space and soil savings.
Plant flavor pairing (tomato in the same soil as basil).
Natural pest-control pairing (onions next to squash to drive away borers).

For separate containers:

Easier to isolate infested plants.
Easier to move plants around balcony for different sunlight requirements.
Easier to meet watering, fertilizer, drainage, and other growing conditions of plants with conflicting requirements.
Comment: Sigh, it's a good answer.  Do you really have to make a commercial out of it with the link in your profile?
Answer: Edit: I thought you were talking about for starting plants--not planting them in their final destination. So, keep that in mind with my answer. See the edit at the bottom of my answer for stuff more specific to your situation.
I have a fair bit of experience starting members of the solanaceae family in one common pot (not necessarily a larger one than I use for single plants, since I tend to use larger-than-normal pots for those). So, I can enumerate advantages and disadvantages of that method, for those plants.
First, the disadvantages of using one container for multiple solanaceae plants:

If your plants get a disease, it may spread between them quicker. A lot of people think this contributes to damping off. While I haven't noticed it affecting that, particularly, I have noticed that it seems to make conditions more advantageous for such as what I think is downy mildew.
The plants won't grow as large as fast.
Plants near the edges may uproot easily after a while, depending on how they're growing.
You'll have to split the roots up eventually and/or take cuttings.
A few of the plants will likely be smaller than the others, or one or more will likely be larger. Sometimes, they're all the same size. I just mean to say that often, some plants will dominate the pot.
People might think you're crazy or ignorant, because this is commonly advised against by experienced gardeners (mainly for the risk of damping off, as far as I can tell).
The plants may get rootbound faster. So, use enough soil for how long they need to be in the same pot.

Second, the advantages of lots of solanaceae plants in one pot:

It saves a lot of space.
The plants are smaller when they mature, but if you split them up, afterward, they can grow huge fast. One plant in a pot tends to take up a lot more vertical space than several plants in a pot.
Less stem between leaf nodes. This is nice because stems can take a lot of space. So, you can get more leaf nodes in a space this way, and potentially more flowers in a given space. However, you'll need to give it the right nutrients for what you want.
You don't need as many containers or as much soil.
Tomatoes and tomatillos seem to split up fairly easily for transplanting. Don't do it until the stems are thicker. If they have root nodules on the stems, it's usually safe to split them up. Peppers might be stunted after splitting up, but if you give them a lot of light a couple days after the transplant, it'll probably help them to adapt. If you give them a lot of light right away, it could be bad since plants with disturbed roots can wither on too much light. I haven't tried splitting up eggplant and ground cherries, yet.

Anyway, it's not for everyone, but there are reasons some might want to do it. The mildew risk seems higher if you have a humid, warm environment with lots of pots of lots of plants. Dim light would also contribute a lot, but my growing area is fairly bright. Wet leaves also can contribute.
As for cucurbits, you should probably only consider cucumbers for this, if any cucurbits at all, and not more than two or three per pot. It's important to know that cucumbers can grow roots at the leaf nodes fairly easily. You can take cuttings of them. Other cucurbits that will root at the nodes might be considerations, too, but I wouldn't count on it.
All in all, most people wouldn't recommend it, I'm thinking, and it's perhaps riskier, but I personally enjoy it at times. These same advantages and disadvantages won't apply to every kind of plant, nor to every person's growing conditions.
Edit: If you're not going to be transplanting your plants, if they're solanaceae plants, even if you have a large pot, if the plants are closer together, they may still be smaller than normal, and they may be less productive. One plant will still likely dominate. This seems to be the case with tomatoes planted in the same spot in a raised bed, anyhow. I would recommend one plant per pot, for outdoor solanaceae plants. For others, it depends.


Half day in Tallinn

Question: In the spirit of Half day in Berlin - after non-classical tourist spots I'd like to ask the community about what can be seen in Tallinn on a Saturday afternoon?
Comment: Tallin isn't *that* big, you can probably manage most of the main tourist spots in an afternoon!
Comment: I think that you will have to be way more precise. The other question is very precise regarding the expectations, and you should do the same, specifically for Tallinn (I suppose you are not looking for Lebkuchen nor German sausages).
Answer: One afternoon is sufficient to see most, if not all, of the Old Town, which is part of the UNESCO World Heritage.
As an alternative, in case of bad weather, or as a complement,  in case you are rushing too fast through the Old Town, you can consider a visit to the Museum of Occupations.  Interesting,  instructive and easy to reach:
http://www.okupatsioon.ee
Answer: Tallinn, if enjoyed slowly allows you to immerse in its energy, which is quite 'high' compared to the more polished neighbours across the Baltic owing to the low spirit rates. Hence you shall find lots of Finns and some russians hanging out regularly in Tallinn thronging its many pubs and night clubs, partying all night, now that the sun almost never sets.
For the day time, you have a couple of museums (naval, art, military, churches) etc and the charm of the old town can be slowly taken in if you wish to. You can always spend a lot of time with architecture and history if you are in those things. Else have a nice bite on some variety food, walk around, feel the energy, join the youth in their celebrations and catch some hot action at the night parties.
enjoy.

Half day in Tallinn


A question about module

Question: Assume R is commutative. Show that an R-module M is irreducible if and only if M is isomorphic (as an R-Module) to R/I where I is a maximal ideal of R.
If I remove the hypothesis that R is communtative, is it result still true?
Answer: Yes, this is true, if you replace ideal by right ideal.
See http://en.wikipedia.org/wiki/Irreducible_module#cite_ref-0

A question about module


How to configure automatic pushing?

Question: How do I configure automatic push in Mercurial and Git?
Sometimes I forgot to push in a computer, and when I move my location, I'm out of the sync with the good code. Is there a way to mercurial and git do this every hour, for instance?
Comment: It's worth noting here that it's a better idea to just learn to push. You really don't want to push after every commit. If you do this, you break some of git's best tools -- you cut yourself off from rebase, `commit --amend`, and other great history-editing tools.
Comment: Just noting that our team lead insists on having developer's local repositories mirrored on a server just for the point of having a live backup; they aren't actually part of our day-to-day process.
Comment: Open your minds. I use source control even when I'm working alone. And I work on different computers.
Comment: Just sometimes that is convenient to me use automatic pushing. I turn off later.
Answer: With git you can use the post-commit hook to push after each commit. To do this you'll need to add an executable post-commit script in your .git/hooks directory. For e.g.
#!/bin/sh
#
# An example hook script that is called after a successful
# commit is made.
#
# To enable this hook, rename this file to "post-commit".

git push --mirror remote

Where remote refers to the name of the remote repo that you are pushing to.
You can also setup cron to execute this script every hour if you wish.
Update
Mercurial has hooks too (but of course). Here is the relevant documentation. I haven't used Mercurial so you'll have to work it out yourself.
Comment: `-f` is quite dangerous. Don't do that.
Comment: --mirror is very dangerous and I'm not sure it's what you want.  If you aren't up-to-date, you'll crush other peoples changes.
Answer: In mercurial you'd put this in your .hg/hgrc
[hooks]
commit = hg push

How to configure automatic pushing?