Is it unethical to teach mindfulness for money?

Question: There are several consulting firms out there that teach mindfulness to corporations as a livelihood. Is it bad karma since they are essentially taking this from the Buddhist teachings, adding their own neuroscience research on top of it and selling it as a product for better productivity and emotional health. On the other hand, many mindfulness centres in the west offer retreats in exchange for "suggested" donations. Does this kind of transaction corrupt the dharma or is it propagating the dharma to a wider audience?
Comment: I would say it is rather ironic that 'Corporations' employ mindfulness for their employees to be more productive and enhance the corporation's achievements which...at the end of the day...do not necessarily bring any benefits of mindfulness to the wider general public customers.
Comment: nope,not at all
Comment: "their own neuroscience research..." pretty sure you have your answer.
Answer: Is it unethical to teach mindfulness for money?

I guess that what's taught as "mindfulness" probably isn't Buddhist Dharma -- for example:

Sharf further notes that this [i.e. Buddhist mindfulness] has little to do with "bare attention," the popular contemporary interpretation of sati [i.e. the mindfulness which is taught by and to corporations], "since it entails, among other things, the proper discrimination of the moral valence of phenomena as they arise."

I think there are reasons why it's traditionally wrong to teach dharma for money -- for example:

Monks shouldn't
Lay people might be typically less able to teach Buddhism than monks or nuns are, and should respect (not try to replace) one of the functions of the Sangha which is teaching

Buddhism isn't very specific about what "right livelihood" is for lay people; but IMO it includes giving good value for money, not making fraudulent claims about the product or service.

IMO because they're not teaching Dharma (#1 above) so the normal reasoning (#2) isn't applicable.
It might be (but isn't necessarily) unethical for #3, e.g. if they make fraudulent (untrue) claims about the benefits of what they're teaching, or if they don't deliver (competently teach) what they promised.
On the other hand, many mindfulness centres in the west offer retreats in exchange for "suggested" donations.
The little experience I have of that is of a group of people renting a room in which to meet -- where a small amount of money per person was volunteered,  a collection to pay to rent the meeting room.
Answer: Good question. Leaving Mindfulness aside for a second, let's consider the question of taking money for Dharma.
In the original Buddhism this was explicitly disallowed but implicitly allowed. Monks could not take money but they could accept 'dana' (donations) in form of food, medicine, and clothes. Rich sponsors such as Anathapindika donated land and sponsored construction of facilities.
In Late Indian Buddhism, as we can see from the story of Naropa and Marpa, it was customary for the student to "offer" (give) the teacher something extremely valuable, such as gold, to indicate respect and seriousness of intent. Indeed, if you don't think Dharma is more valuable than gold, can you be considered a serious student? This custom was carried on in Tibetan Buddhism, where money "offerings" to the teacher at the end of the lecture are practiced to this day.
A modern teacher I highly respect once said that people do not value something they get for free. He insists on charging money for retreats and training sessions. According to him, people take it more seriously when they feel it has a cost. My Zen Master had "membership fee" that permanent students had to pay. He never enforced it of course, but it has been declared. My local Nyingma temple always sells tickets for teaching events, but never checks them at the door, so everyone can come and listen whether they have money or not. Thousands of Buddhist authors and translators sell books on Amazon and other bookstores for much higher amount than the cost of paper and printing.
I think this sets up enough precedence to not demonize taking money for teaching Dharma. I personally would like to see Buddhism getting as popular and accepted by mainstream society as therapy, personal coaching, and holistic practices like Tai-Chi & Qigong. Treating it as any other wellbeing training, including the taking of money, would help with adoption. There are always the normal concerns of fair price, fair advertisement, fair customer retention methods, fair customer service - but I think this could be controlled by the civil society's free market mechanisms, as well as existing legislation in place in most countries.
Now, to get to your Mindfulness question, Mindfulness is not strictly speaking a form of Buddhism. Even though it was inspired by Buddhism it does not provide a holistic ethical and philosophical system for someone to follow. In some sense Buddhism is like science: the laws of physics are not anyone's intellectual property and can't be patented. If someone takes one of these laws of principles, and builds a commercial product around it -- a product that people find helpful and good -- the physicists do not file a lawsuit for patent infringement, do they? So I don't think we should be this defensive about someone taking an idea from Buddhism and using it for the benefit of people, even if they charge money for it.
In my opinion, Dharma gets more "corrupted" by not fully understanding its principles, by not applying them in real life, and by not passing them on to the next generation -- than by the charging of money. What hurts Dharma, in my opinion, is parroting the texts with only a superficial understanding, and encouraging superstitious attachment to traditional skillful means - without making an effort to understand and transmit the meaning and purpose behind the ideas.
What I think needs to happen to help "propagating the dharma to a wider audience" is a serious effort to translate the principles behind dharma to a modern secular language, and to show how dharma benefits all aspects of regular life. Offering commercial Mindfulness courses to a wide secular population is a tiny step in the right direction.
Answer: Yes, it is unethical.
Vinaya Pātimokkha sekhiya Pādukāvagga Navama:

"Formerly, monks, in Benares, the wife of a certain low class man came
to be pregnant. Then, monks, this low class woman spoke thus to this
low class man: 'Sir, I am pregnant; I want to eat a mango.'
'There are no mangoes, it is not the mango season,' he said.
Now at that time the king had a mango tree with a perpetual crop of
fruit. Then, monks, that low class man approached that mango tree;
having approached, having climbed up that mango tree, he remained
hidden. Then, monks, the king together with the brahmin priest,
approached that mango tree; having approached, having sat down on a
high seat, he learnt a mantra. Then, monks, it occurred to that low
class man:
'How unrighteous is this king, inasmuch as he learns a mantra, having
sat down on a high seat. This brahmin also is unrighteous, inasmuch as
he, having sat down on a low seat, teaches a mantra to (someone)
sitting on a high seat. I too am unrighteous, I who for the sake of a
woman, steal the king's mangoes. But all this is quite gone,' (and) he
fell down just there.
Neither knows the goal,
neither sees dhamma,
Neither he who teaches the mantra,
nor he who learns according to what is not the rule.
My food is pure conjey
of rice flavoured with meat,
I do not therefore fare on dhamma,
dhamma praised by the noble.
Brahmin, shame on that gain of wealth,
(that) gain of fame;
That conduct (leads) to falling away
or to walking by what is not the rule.
Go forth, great brahmin,
for other creatures boil,
Do not you, following what is not the rule,
from that break like a pot.

Mahasupina Jataka:

"I saw rancid buttermilk being bartered for precious sandalwood worth a fortune in gold. This was my eleventh dream. What shall come of it?"
"This will happen only in the distant future, when my teaching is waning. In those days, there will be many greedy, shameless bhikkhus, who for the sake of their bellies dare to preach the very words in which I have warned against greed! Because they desert the Truth to gratify their stomachs, and because they sided with sectarians, their preaching will not lead to Nibbana. Their only thought as they preach will be to use fine words and sweet voices to induce lay believers to give them costly robes, delicate food, and every comfort. Others will seat themselves beside the highways, at busy street corners, or at the doors of kings' palaces where they will stoop to preach for money, even for a pittance! Thus these monks will barter away for food, for robes, or for coins, my teaching which leads to liberation from suffering! They will be like those who exchanged precious sandalwood worth a fortune in pure gold for rancid buttermilk. However, you have nothing to fear from this. Tell me your twelfth dream."
Answer: What is being taught is not the teachings of the Buddha but another doctrine manufactured by others. Therefore, its not unethical in the sense of "stealing" something from Buddhism. However, it is bad karma because the "mindfulness" being taught is the suspension of moral judgment.
The word "mindfulness" merely means to "remember" or "keep in mind". An assassin that must stalk a victim to shoot them must have "mindfulness". However, the mindfulness of an assassin is not Buddhist "Right Mindfulness" ("Samma Sati").
Similarly, the corporate mindfulness that teaches to suspend moral judgment in favour of having equanimity towards all corporate objectives & directives is not Buddhist mindfulness. Since Corporate Mindfulness is not Buddhist Mindfulness, it can be sold for money.
Answer: It is ethical if it brings cessation of and eases suffering of all other beings.
I once listened to Ajahn Brahm's talk when he described it is absolutely fine to have money and be rich, but in a right way, helping people, refraining from lying and by not making others suffer in the process.
Answer: Teaching ''samatha'' bhavana for money is not a much  big problem,But when it's to ''Vipassana'' bhavana that's not ethical and suitable..Because Lord buddha's the founder of vipassana meditation ,and before the era of buddha there were samatha bavana and it's also taught in other religions..So vipassana meditation is only found in Buddhism,It's not ethical to get money for teaching vipassana..
In buddhism mostly buddhist monks are the teachers,Buddha had said them not to accept money in any occasion,So that also suggest getting money for something uniquely in buddha's learning isn't suitable
Answer: To teach mindfulness is one thing;
To teach the dharma is another thing.
Supplementing my original comment to the question and simply put:
If the corporation is unethical, anything/any means that supports this corporation, is unethical.


Do dark pools have to declare the volume transacted at the end of the day?

Question: While dark pools can keep their transactions secret from the public exchanges during trading hours, are they required by regulation to declare the volume transacted after the market close at the end of the day? I was wondering whether the end-of-day stock price data provided include the volume transacted in the dark pools.
Comment: my understanding is that they don't have to, they are just market participants exchanging shares away from the exchange, like if a group of people met up at the park and were exchanging shares. at the same time, I think certain market participants need to report volume regardless of where they do the exchanges. Looking forward to an official answer though
Comment: Is this question about the USA?
Answer: Members of the Federal Reserve System keep track of what money a bank has (if it's not in the vault), who owns what shares of stock, who owns what bond, etc.
The part of the Federal Reserve System that tracks stock ownership is the Depository Trust Company (DTC). They have a group of subsidiaries that settle various types of security transactions.

DTC is a member of the U.S. Federal Reserve System, a limited-purpose
  trust company under New York State banking law and a registered
  clearing agency with the Securities and Exchange Commission.

There's lots of information on their website describing this process.

DTCC's subsidiary, The Depository Trust Company (DTC), established in
  1973, was created to reduce costs and provide clearing and settlement
  efficiencies by immobilizing securities and making "book-entry"
  changes to ownership of the securities. DTC provides securities
  movements for NSCC's net settlements1, and settlement for institutional
  trades (which typically involve money and securities transfers between
  custodian banks and broker/dealers), as well as money market
  instruments.

Black pools are trades done where the price is not shared with the market. But the DTC is the one who keeps track of who owns which shares. They have records of all net transactions2.
The DTC is the counterparty for transactions. When stock moves from one entity to another the DTC is involved.

As the central counterparty for the nation's major exchanges and
  markets, DTCC clears and settles virtually all broker-to-broker equity

1. This is the link that shows that settlements are reported on a "net basis".
2. If broker A sells 1000 shares of something to broker B at 8 and then five minutes later broker B sells the 1000 shares back to A, you cannot be sure that that total volume will be recorded. No net trading took place and there would be fees to pay for no reason if they reported both trades.
Note: In dark pool trading quite often the two parties don't know each other. For shares (book-keeping records) to be exchanged it has to be done through a Clearing House.
Answer: "On June 2, 2014, to stem public outrage over claims of rigged markets, FINRA, the self-regulator and good buddy of Wall Street that conducts Wall Street's private justice system, began to report publicly the three-week old trading data from the Dark Pools. But instead of providing daily reports with execution times for stock trades included, the data is lumped together for the entire week. That's makes it a lot harder, if not impossible, to see if there is collusion happening by a banking cartel."  --Wall Street on Parade.
Also, the SEC has raised concerns: "There is a risk ATS operators may be internalizing the transactional activity and selling
institutions securities at full price that, in essence, may not exist"
read that again: "securities that don't exist"!
https://www.sec.gov/comments/s7-23-15/s72315-25.pdf
And finally, Lucy Komisar:
https://youtu.be/5wlcQfZW0a8


Can I sell computer with pre-installed software with Apache 2.0 License?

Question: Can I sell computer with pre-installed software with Apache 2.0 License? Provided that I do not charge for software or license, only for hardware with some margin?
Comment: Is there any reason why you think that might not be possible/permitted?
Comment: @BartvanIngenSchenau perhaps the software+hardware is a derivative work? but apache allows selling so I don't see the problem there. Perhaps the source code must be supplied along with the computer?
Comment: @BartvanIngenSchenau In Germany, the problem could be that you are allowed to ignore the license if you **run** software that you legally received. I don't know about the Apache license, but the consequences in the case of the AGPL are clear: You can operate some AGPL-licensed software-as-service without having to give others access to the source code.
Answer: It is perfectly lawful to sell a computer with free software pre-installed.  Indeed, you may charge whatever you like; not just for the hardware, but for the software, too.  The FSF are clear about that.
What you may not do is deliver it without user freedom, so you may not attempt to legally prevent the user from using, copying, modifying, and then redistributing the software thereon as they wish.  If the software is covered by a copyleft licence, such as GPL, you must provide the user with source code to assist them in this.  If the GPL is v3, you may not attempt to prevent the user exercising their freedoms by technical means (eg, DRM), either.


Is it possible to spread holy water on a weapon like you do with poison?

Question: I'm wondering whether a character could spread holy water over his sword or axe and then hit an undead and on the first hit, inflict an extra 2d6 as if the holy water had been thrown at the undead. After all, we can do that with poison and holy water is like poison to undead creatures.
Answer: By the book? No.
As a house rule?
Consistency may be a problem. Poison for applying on blades is usually described as a paste or oil - something that can stick for a while, as opposed to an ingested poison which would be watery.
The holy water itself wouldn't stay on the blade long enough to hit something with. It may be able to (temporarily) make the weapon holy, but this would be entirely up to the DM, and not covered by the rulebooks.
Comment: @JonStory "What if I filled my scabbard with holy water?"  Presumably, your sword would rust.  A blade that is not oiled corrodes very quickly.  Holy water would slick right off an oiled blade.
Comment: @LegendaryDude it's simple, we bless the oil. Holy oil.
Comment: What if I filled my scabbard with holy water? Then the first attack or two would presumably be more powerful. More importantly, why are we using swords instead of water pistols?
Comment: In a very cold environment (glacial rift of the frost giants for 200, Alex) you could freeze it onto the blade. :)
Comment: If you fill the scabbard, the water wil lbe gone the moment you do any swing movement with the blade. Fill a dagger scabbard, take dagger out, hit enemy - MAY work, but swinging a sword? No.
Answer: Shape water cantrip can coat the weapon for an hour
Work with your DM to use two of the features of the shape water cantrip to temporarily coat the blade (for an hour) with frozen holy water.  This would work better in a very cold environment than in and around a pool of lava or a red dragon's lair.
By RAW, it should work.
From the Elemental Evil supplemental material1 (p. 21), you can apply two features of the spell and keep then going for an hour -- (1) shape the water to perfectly fit onto the weapon, and (2) freeze it into that shape.

Shape Water
Transmutation cantrip
  Casting Time: 1 action
  Range: 30 feet
  Components: S
  Duration: Instantaneous or 1 hour [depending on effect]

This effect can be used for at most one hour.

You choose an area of water that you can see within range and that
  fits within a 5-foot cube.

Holy water, in a vial, fits within a 5' cube.  You could pour it into a bowl or helm while doing this to make the process easier, but that's something to work out with your DM.

You manipulate it in one of the following ways:  [...]
  - You cause the water to form into simple shapes and animate at your
  direction. This change lasts for 1 hour.
  - You freeze the water, provided that there are no creatures in it. The water unfreezes in 1 hour.
If you cast this spell multiple times, you can have no more than two
  of its non-instantaneous effects active at a time, and you can dismiss
  such an effect as an action.

There's one weapon, coated with a nice layer of holy water for the next successful attack on a creature susceptible to holy water damage.
Do you really need to freeze it?  Maybe not.  Depending on how you and your DM interpret the spell effect, simply shaping it to the contours of the weapon might suffice.  You could also shape it to fit as a weapon your are proficient with, if one of those is "a simple shape."  Again, work with your DM to work out the fiddly details.

I would recommend that the damaging effect be limited to one successful hit against an undead creature, or fiend, that is susceptible to holy water damage such that the hit does the full vial's damage (2d6 radiant) when hit with the coated weapon.  (Sort of like how poison doesn't last forever on a weapon).  Otherwise, this approach would be a little OP in terms of using a cantrip to enchant a weapon.
1This spell is also in Xanathar's Guide to Everything (p. 164).
Comment: I like the idea, but would frozen holy ice still do damage or would it mostly just fall to the ground in pieces?
Comment: @Hennes The idea is that it does damage on contact with the undead/fiend; that's the magical thing about the holy water.  I can see your point.  That's why the old "work with your DM" is a good idea here.  (If you look at the spell description, you can dismiss any of the features .... so let it melt when you score that hit? Might be too fiddly at that point ... since it takes an action to dismiss ...  )
Answer: RAW, you need to make a ranged attack with the holy water, as an improvised weapon.
It's right there on PHB151
Should you houserule it, I would suggest that allowing the full effect of the holy water in addition to the effect of the underlying weapon breaks the action economy. Also, possibly the holy water economy.
Comment: Oh, here's an idea - make a *melee* attack with the holy water as an improvised weapon! Basically, smash the flask over them. Not entirely RAW, but close.
Comment: A non-improvised weapon for delivering holy water is the aspergillum: https://en.wikipedia.org/wiki/Aspergillum
Comment: About the economy, some spells allow you to add some damage similar to that to your weapons and such last for the duration of the spell, so I do not think it would be that bad.
Comment: Yes. I know you can throw it. I was wondering about the application on a weapon as that does not seem to be mentioned and thus probably no allowed.
Comment: @Adeptus which is probably a much-better way to implement the close-in holy water attack than applying the disadvantaged 5' ranged attack that RAW provide for....
Answer: I brought this same idea up to my DM because I wanted to apply Holy Water to my arrows or rapier (I'm playing a rogue that likes to use poison: holy poison!).
The house rule we came up with was I have to make a 20+ poison check to craft a poison from the holy water with my poison kit.
A successfully crafted poison using this approach deals 1d6 radiant damage to a fiend or undead.  That's a combination of (1) rules on how to apply poison to weapons, (2)  the rules on holy water doing radiant damage, and (3) using an ability check per Chapter 7.
Comment: Could you expand on this by showing that this isn't an option by default (probably by summarizing where you and your GM looked for information before making the homerule) and expand on how this rule has performed in-game?
Comment: I like the idea of being able to use an oily element so it sticks to the weapon, like we do with a poison. As for an arrow, I'm wondering how much of it would really stick to the tip... maybe the damage could increase by just 1d4.


Is there a French equivalent for "FYI" (for your information)?

Question: I understand that the French translation of "for your information" is "pour votre information", but is the acronym PVI used?
Comment: It depends on the country.  French is spoken in France, Canada and a few african countries.  You will get contradictory answers.  In Geneva for instance (bordering France) I always see "pour information" in full.
Answer: I've never seen "pour votre information" abbreviated as "PVI". If I saw "PVI", I don't think I would guess what it means.
"Pour votre information" is commonly abbreviated to "pour info", both in informal speech and in informal writing. It's common in corporate emails or chat (when formality isn't required).
Comment: "Pour information" est parfois abbrégé "PI" (vu dans des courriels). Jamais vu PVI, en revanche.
Comment: People would be far more likely to write FYI if they know English, and you could expect some people to understand it. Not very French, though.
Comment: Aussi PTI (Pour Ton Information)
Answer:
Pour votre information

works; in most contexts you could also shorten it to:

Pour information.

In contexts where it's used with a colon at the start of a sentence (for example, "FYI: there is a conference on flying sausages [...]), you could simply use,

Information : il y a une conférence sur les saucisses volantes [...]

As far as using the acronym PVI is concerned, I think it's a lot more rare in French; I've never seen it myself. However, there is a wikipedia page that references it, and it's also reference a few random places on the web. I didn't succeed in finding an actual dictionary reference, so probably better to avoid using it unless you're really cramped for space - it's more likely to cause confusion than anything else.
Comment: Never seen "PVI" in my entire life. Please don't use it.
Comment: In casual conversation, "pour ton/votre information" is usually shortened as "pour info".
Comment: 'PVI (Pour votre information) : Le message est à titre indicatif et aucune action n'est attendue de la part des destinataires.  https://jacquesbizard.ecoleouestmtl.com/wp-content/uploads/2019/08/Guide-des-bonnes-pratiques-du-courriel.pdf
Answer: pi is quite often used in my company at least
Answer: The abbreviation "PI" is very often used in business conversations.
Answer: There is not an exact French equivalent for FYI, but a similar phrase would be "pour votre information" or "PVI."
Answer: It certainly depends on the environment, but I always use "FYI" and see it used that way. At least in business/technology, this is one of these things that sneakily crawled into our language.
Answer: I've heard « pour ta gouverne » as well, but I believe this is soutenu.
Comment: Yes and no ... "Pour ta gouverne" also means FYI (not often seen in writting), however it is mostly condescending ("I'm telling you this info because it seems you're too dumb to know it") and not particularly soutenu


Java UserDefinedFileAttributeView

Question: When I add a new UserDefinedFileAttributeView attribute to a file, where does Java store this information?
There are no additional files in the directory, the file does not have any new attributes or details when I view the file properties.
My code:
String versionAttrName = "report.version";
try {
    Path path = FileSystems.getDefault().getPath(filePath, "");
    UserDefinedFileAttributeView view = Files.getFileAttributeView(path, UserDefinedFileAttributeView.class);
    view.write(versionAttrName, Charset.defaultCharset().encode(newVersion));
} catch (IOException e) {
    System.out.println("7 - Error saving version to file! - "+ filePath + " - " + e.getMessage());
}

Comment: Did you check your user directories and `programdata` directories... I would recommend doing a hard drive search, will be the fastest way to find the file :)
Comment: Any thoughts on what to search for? Haha, I have no idea what file name/type Java would use
Answer: These metadata are stored using file system's "extended file attributes" (see wikipedia).
I could not find any comprehensive list of file systems being supported (it is definitely JVM specific), so you should definitely test in on all platforms you plan to support. But this answer lists some and this mentions some details about Linux. Hope this helps.
Answer: It depends on the platform you're running under.
As per the OpenJDK documentation: The details of such emulation are highly implementation specific and therefore not specified.
However testing on Windows indicates it uses NTFS Alternate Data Streams:
PS C:\test> Get-Item -Path C:\test\asdf.txt -stream *

   FileName: C:\test\asdf.txt

Stream                   Length
------                   ------
:$DATA                        0
myaltstream                1337

On linux it uses extended attributes.
Not sure about others - hope this helps :)

Java UserDefinedFileAttributeView


"Except of" vs. "except for" vs. "apart from"

Question: I've used to say "except of" for a lot of sentences but recently someone noted (or corrected) me "apart from". I don't really remember the context that this correction was in. Anyway, after sometime I saw this article in Cambridge which is talking about the difference between "except for" to "apart from". That says that my habbit to say "except of" is a mistake?
Comment: It's possibly also worth noting that most places where you can say "except for," you could also just say "except." For example, "all flowers, except for roses" is pretty much the same as "all flowers, except roses." There are a few cases where "except for" means something different (for example, "I **would** hate all flowers, except for roses" means something slightly different from "I hate all flowers, except roses" and you couldn't leave "for" out of the first one). But mostly, you won't go wrong if you just delete the preposition altogether.
Comment: Yes, I don't think I've ever heard of "except of", but I have heard of "except for".
Comment: Yes, it is a mistake. And please note: I used to say, not: I've used to say. except of is not grammatical. correct usage for have used: "I've used a stove, but I am not a good cook."
Answer: As noted in the comments, 'except of' is wrong. This error may be caused by confusion with with the exception of, as in With the exception of Jim, everyone must report for work at 8am.
As with the example above, sometimes these confusions arise because different forms of a word use different prepositions, or one form has a preposition while the other doesn't (e.g. discuss the problem (no preposition), have a discussion about the problem).


How to KDE + awesomewm?

Question: Is there a way to configure awesomewm as windows manager but running KDE as desktop environment?
Answer: You need to mask the KWin systemd service and create a new user unit for awesomewm. See the entry in the Arch wiki.
Answer: The window manager that KDE uses is kwin, so you can replace it with any other window manager, including awesomewm. One possibility of doing this is setting the KDEWM environment variable to the binary of your window manager before running startkde.
Therefore yes they can coexist together more or less as you want. In my case I have never done it with KDE, but I was using Gnome with awesomewm for a while. The truth is that joint use is something uncomfortable and unnecessary. I finally stayed at pure awesomewm. But this is just personal opinion.
Comment: This method will not work with current versions of Plasma.

How to KDE + awesomewm?


Describing the Lie algebra structure of a semi-direct product of Lie groups

Question: Let $G$ and $H$ be Lie groups with Lie algebras $\mathfrak{g}$ and $\mathfrak{h}$. Suppose $G$ acts on $H$ by automorphisms, i.e. there exists a lie algebra homomorphism $\phi:G\to Aut(H)$. I want to find the Lie algebra of $G\ltimes H$. As a manifold, $G\ltimes H$ is diffeomorphic to $G\times H$ hence the Lie algebra of $G\ltimes H$ is the vector space $\mathfrak{g}\oplus\mathfrak{h}$. However, the groups $G\times H$ and $G\ltimes H$ need definitely not be isomorphic, so their Lie algebras need not be either. I want to describe the bracket structure on Lie($G\ltimes H$). I know that $\phi$ induces a Lie algebra homomorphism $\mathfrak{g}\to Lie(Aut(H))$, but how can I use this?
Comment: Do you mean Differential Geometry, Lie groups and Symmetric spaces?
Comment: I think this is in Helgason's book somewhere.  Do you have it?
Comment: Yes, that's the one.  Now that I've gone and thumbed through it, I'm not so sure.  But if you have it, look there.
Comment: I can't find the book. Do you have an idea of the proof?
Comment: The Lie algebra of a semidirect product is a semidirect product (of Lie algebras). You want to differentiate the action of $G$ on $H$ at the identity to get a map $\mathfrak{g} \to \text{Der}(\mathfrak{h})$, then take the semidirect product wrt this map.
Comment: Why do I get a map $\mathfrak{g}\to Der(\mathfrak{h})$?
Answer: There are two possible conventions for semidirect product, but let's suppose you're using the following one
$$
(g_1,h_2)\cdot(g_2,h_2) = (g_1g_2,h_1(\phi(g_1)h_2)).
$$
Employ the notation $\phi_g:H\to H, \  \phi_g(h) := \phi(g)h$ and $\phi^h:G\to H,\ \phi^h(g) := \phi(g)h$, and define
$$
\phi_g':= T_{e_H}\phi_g:\mathfrak{h}\to\mathfrak{h}, \qquad \dot{\phi}^h:=T_{e_G}\phi^h:\mathfrak{g}\to T_hH.
$$
So
$$
(g_1,h_1)\cdot (g_2,h_2)=(g_1g_2,h_1(\phi_{g_1}h_2))
\quad\textrm{and} \quad (g,h)^{-1} = (g^{-1},\phi_{g^{-1}}h^{-1}).
$$
Calculating $(g,h)\cdot(k,l)\cdot(g,h)^{-1}$, and differentiating wrt $(k,l)$, it is not difficult to show that the adjoint action of $G\ltimes H$ on $\mathfrak{g}\ltimes \mathfrak{h}$ is given by
$$
\operatorname{Ad}_{(g,h)}(\xi,\eta) = (\operatorname{Ad}_g\xi,\operatorname{Ad}_h(\phi'_g(\eta))+\sigma_h(\operatorname{Ad}_g\xi)),
$$
where
$$
\sigma_h:\mathfrak{g}\to\mathfrak{h}, \qquad \sigma_h(\xi):= h\cdot(\dot{\phi}^{h^{-1}}\xi).
$$
Here $\dot{\phi}^{h^{-1}}\xi\in T_{h^{-1}}H$, and $h\cdot $ denotes the derivative of left multiplication by $h$ (i.e., in general we define $h_1\cdot v_{h_2} := T_{h_2}L_{h_1}(v_{h_2})$, where $L_{h_1}:H\to H$ is left multiplication by $h_1$).
Now taking the derivative of this wrt $(g,h)$, we obtain an expression for the adjoint action of $\mathfrak{g}\ltimes\mathfrak{h}$ on itself (and hence the Lie bracket):
$$
[(\xi_1,\eta_1),(\xi_2,\eta_2)] : =\operatorname{ad}_{(\xi_1,\eta_1)}(\xi_2,\eta_2) = ([\xi_1,\xi_2],[\eta_1,\eta_2]+\xi_1\cdot\eta_2 - \xi_2\cdot\eta_1),
$$
where
$$
\xi\cdot\eta := (\dot{\phi}')_\xi\eta = (\dot{\phi}')^\eta\xi = T_{(e_G,e_H)}\phi(\xi,\eta),
$$
(in the final equality thinking of $\phi:G\times H\to H$).
Comment: $T_{(e_G,e_H)}\phi(\xi,\cdot)$ is: $\phi_g \in Aut(H)$, so $\phi_g(hlh^{-1}) = \phi_g(h)\phi_g(l)\phi_g(h)^{-1}$. Differentiating wrt $l$ gives $\phi_g'(\operatorname{Ad}_h\eta) = \operatorname{Ad}_{\phi_g(h)}(\phi_g'(\eta))$. Then differentiating wrt $h$ gives $\phi_g'([\eta_1,\eta_2]) = [\phi_g'(\eta_1),\phi_g'(\eta_2)]$. Finally differentiating wrt $g$ gives the derivation property.
Comment: I'm late to the party but I just had to understand how that computation worked and this post was extremely useful. [I wrote up a little thing](https://www.asc.ohio-state.edu/terekcouto.1/texts/semidirect.pdf) (mostly for myself and crediting this answer, with some notations changed just as matter of taste), but maybe it can be useful for whoever else comes across this too.
Comment: Thank you for sharing, @IvoTerek - I've saved a copy myself :) Another place you can find a proof of this result (with yet again different notation) is Section 2.2.4 of [Momentum Maps and Hamiltonian Reduction](https://link.springer.com/book/10.1007/978-1-4757-3811-7) by Ortega and Ratiu. I'm not sure if I wasn't aware of this reference in my original answer (I definitely knew the book), or just forgot to include it.
Comment: Is the map $T_{(e_G,e_H)}\phi(\xi,\eta)$ a derivation of $\mathfrak{h}$?
Comment: I was under the impression that $Ad$ is used to denote the adjoint map at the level of Lie groups and $ad$ is used to denote the differential of the adjoint map. You seem to be using $Ad$ for one time derivation, and $ad$ for derivation in another coordinate.. is that so!
Comment: I understand everything you have written till the description of adjoint map $(G\rtimes H)\times (\mathfrak{g}\times \mathfrak{h})\rightarrow (\mathfrak{g}\times \mathfrak{h})$.. after that I am lost (starting with "now taking the derivative").. can you please explain a little more…
Comment: Ok. First off, do you understand why the derivative of $gkg^{-1}$ with respect to $k$ in the direction $\xi$ is $\mathrm{Ad}_g\xi$? This is essentially the definition of $\mathrm{Ad}$.
Comment: I wasn't aware of that book, thank you!!


replacing lower jockey wheel

Question: my lower jockey wheel is a plastic affair 12tooth that has no bearings just a bushing. It gives a lot of friction and a lot of side to side movement. I wish to replace it with perhaps a metal one with sealed bearings but I can only find 11tooth and 13 tooth, would either of these work and which one??
Comment: A different size may cause the chain to rub or interfere with the tab many derailleurs have in between the pulley wheels. Pulley wheel sizes also affect the way a derailleur tracks the cassette (mainly in upper pulleys) and the derailleur's total chain wrap capacity (mainly in lower pulleys), but one tooth probably isn't a huge difference. What is the model number of your rear derailleur? For some Shimano RDs, pulley wheels are still available from the factory, but the small parts catalog has a more recent part number than the exploded view. I ran into that issue with my RD-M772.
Comment: @Michael I lateral play on *upper* pulley wheels is definitely by design. I was under the impression that the lower pulley wheels are not supposed to have that float. Am I correct?
Comment: The side-to-side movement is intentional. I doubt it adds much friction. I'd clean it and install it with a light grease (or maybe even chain lube). I think 13 teeth *could* be problematic if there is not enough distance between the pulley wheels.
Comment: @Weiwen Ng That is correct to the extent of my knowledge. The floating upper pulley isn't strictly required either. It helps compensate for poor indexing, but a laterally rigid pulley should give crisper shifting if you know how to adjust it right.
Answer: Jockey wheels with bushings are pretty common. (NB for readers not familiar: bushings, aka plain bearings, just have the axle rotate within a plastic or bronze sleeve rather than supported by bearings. The bushing materials are self-lubricating.) Also, the plastic in question is a pretty common material for jockey wheels, and it is not intrinsically fragile in that application. That was discussed on a previous Stack Exchange post. Furthermore, the jockey wheel may appear to have relatively high friction when spun by finger, but we don't push the pedals with our fingers. The amount of friction is pretty marginal in the context of your total power output. That said, play in the lower jockey wheel is probably a sign that it's wearing out. Note that play in the upper wheel is by design.
On performance road bikes, one of the minor new trends is to replace the jockey wheels with slightly larger ones, e.g. Kogel Bearings makes 12t upper and 14t lower pulleys for current generation Shimano road groups, which come stock with 11t pulleys. However, the clearance between the upper pulley and the smallest cog is a potential issue, and some Shimano groups can only take 11t replacement upper pulleys. On the lower pulley side, there may be interference between the pulley teeth and the cage.
Thus, extrapolating to your group, if you are dead set on metal jockey wheels, it would be safest to get the 11t pulley. A larger jockey wheel may work, but it's not guaranteed. At minimum, you'd need to provide your derailleur make and model. As described in the first paragraph, I'm not convinced it's necessary for most riders to upgrade to metal pulleys and cartridge bearings. In interest of full disclosure, I did upgrade the jockey wheels on my road and gravel bike to 12/14t Kogel units, which are aluminum with ceramic bearings. That was for performance reasons, but the expected difference in drivetrain friction is small, maybe 0.5-1W at 250W input power. I have typically seen long life out of the stock plastic pulley wheels.
Comment: Looks like Ultegra has two ball bearings on R8000. Two ball bearing pulleys have been on Ultegra since 6800, XT since M773, and Saint since M820, going by the genuine parts catalog.
Comment: Plastic or bronze are probably the most common bushings, but some nicer Shimano RDs used a sealed ball bearing for the tension pulley, and a sealed ceramic bushing for the guide pulley.
Comment: @Pisco I believe the arrangement on the current generation of Shimano road units is that Dura Ace has bearings in both, Ultegra has a bearing in one and a ceramic bushing in the other, and 105 has two bushings.
Comment: I've got two ball bearings in my XT M8000 RD. I believe the XTR has a hybrid ceramic bearing in the guide pulley.

replacing lower jockey wheel


The possibility of impossible

Question: While thinking about the possible and impossible I came into the following conclusion. Some people say that nothing is impossible. But by saying that "nothing is impossible" they automatically preclude the possibility of the impossible. Which means that the possibility of the impossible is impossible. (If there's is something that is impossible, it's the impossible itself). Then it's not true that nothing is impossible.
(I don't know if I'm getting crazy or dumb by thinking this way or am I actualy right)
Comment: You are doing correct. It is just recursion. Impossible is a conception. So it is already real the minute you think/mention it. What people are meaning by the nothing is impossible phrase is that NO ONE yet found what is truly impossible. Sometime somebody thought its impossible to fly, yet planes are here, and so forth. SO! it is VERY difficult to find something that is truly impossible. BUT. Impossibility itself is possible, because we already understand what it means.
Answer: Let Γ be the class of all impossible sentences, i.e., Γ = {φ : ¬◊φ}. Someone claiming that nothing it impossible is simply claiming that Γ = ∅. That commits them to the thesis that no formula is necessarily false, not that "the impossible is impossible" (whatever that means). The thesis is obviously false (i.e. Γ is nonempty), not because "impossible is impossible" is a tautology, but simply because there are sentences, such as (φ ∧ ¬φ) that are necessarily false (i.e. impossible) and thus belong to Γ. That's it.
It's always a good idea to model some interpretation of what's being said in a precise framework that will allow you to settle questions of truth without getting into contradictions and paradoxes. So for example, instead of formulas being impossible we could talk about actions beings unrealizable. The claim that nothing is impossible would then be that the set of realizable actions (for a given agent) is the entirety of the action space. In that framework, we would isolate an action that because of practical or theoretical reasons couldn't be realized (by the agent), contradicting the claim that she can do anything.
Comment: This is absolutely right. The question as asked involves an abuse of language.
Comment: It's a bit of a leap of faith to go from "nothing is impossible" to Γ = ∅ - the common usage of such a sentence is more like 'for all practical results/states there exists some course of actions that has a nonzero chance of success', or 'all imaginable world states have a nonzero chance of existing'. And certainly there are formal logics where (φ ∧ ¬φ) is *not* neccessarily false; a logic system can only be complete or noncontradictory but not both, so any complete logic will have possibilities of (φ ∧ ¬φ).
Comment: You understand that by writing "math" you did not levitate above language paradoxes but rather dived even deeper? Without __LANGUAGE__ around them your math symbols are meaningless.
Comment: @AsphirDom (1) Where's the paradox? My aim was to explicate "nothing is impossible" in one particular way in order to avoid getting tangled in nonsense. Fitch's is a paradox, Preface is a paradox, Surprise is a paradox, Russell's is a paradox, Burali-Forti's is a paradox, Curry's is a pradox, you get the idea... (2) As regards the symbols, I could eliminate them, but that would not be helpful to anyone. I could rewrite what I said using simpler symbolism, but like everyone else, I have my tastes and yesterday I felt like talking of sets of sentences instead of using quantifiers explicitly.

The possibility of impossible


How do I install Ubuntu without using a LiveCD/USB?

Question: There appear to be two types of Ubuntu installations: 'live' installations (typically USB or CD) and what I'm going to call 'full' installations (typically on an internal HDD).
Full installations can use "Startup Disk Creator" to create live installations, and live installations ask if you would like to try Ubuntu or install to a hard drive, creating 'full' installations.
How can I create another 'full' installation on another partition/disk, without creating an intermediate bootable 'live' medium? This seems like it should be simple.
Example Scenario:
A computer with four partitions: swap, /home, / , and one blank. Ubuntu 12.04 Desktop is currently installed on partition 3. I would like to install 12.04-server on the 4th partition. I have the .iso saved on the drive (/home partition). How do I perform a full (not 'live') install of 12.04-server to the fourth partition without buying a USB stick or CD drive?
Comment: It's right here http://askubuntu.com/q/157055/2973
Comment: wojox is correct, that way should work fine.
Answer: If you mean to do this in the same way that Archlinux is installed, there is the debootstrap command which may be of help.
You can create the necessary partition with cfdisk (or gparted) then format it correctly (probably ext4) and mount it.  You should then run debootstrap and chroot into the formatted partition before using aptitude to finish the installation.
I'm not exactly sure which packages ubuntu 12.04-server installs as part of the base installation, so I can't tell you exactly what you need to install with aptitude.  Also, this will not give you a nice GUI installation process.
After installation and after exiting the chrooted environment, you should run grub-install before unmounting the drive.


Illustrator CC 2015 - create area and add color

Question: I'm just starting Illustrator and when i created my logo, I saw that I can't fill the areas with color or some areas are not like i want them to be and it's just weird how they are filled. Idk how to fix that. I used the Ellipse tool and pen tool to create that logo. Thank you for your help! [1]: https://i.stack.imgur.com/bdiZ6.png  [2]: https://i.stack.imgur.com/h7fBG.png
Comment: You may benefit from reviewing some of the basic Illustrator tutorials Adobe provides. [**SEE HERE**](https://helpx.adobe.com/illustrator/tutorials.html)
Comment: You are trying to fill open paths, that's why it's not working.  You need closed paths for the fills to appear in the areas you expect.  Watch this tutorial: [Adobe Illustrator: Open & closed paths](https://vimeo.com/106891346). This is really basic stuff.  You need to understand how to walk, before you can run.
Answer: You are lucky - you work with Illustrator. If you were in Affinity Designer or Inkscape the things would be harder. In Affinity Designer you would need to redraw nearly all to get the wanted fillable areas or at least draw and join numerous new parts to existing curves to get closed shapes. In Inkscape it's often possible to recombine the paths with minimal redrawing, no matter are they open or closed.
My suggestion: Learn how to use Illustrator's  Shape Builder tool. It's easy although it's not an effect which could be removed later. It literally builds new closed shapes from existing edge shapes. The edge shapes can as well be open or closed paths.
Other possible tools: Live Paint and the Shaper - more complex, but they do not work destructively.
Comment: This isn't accurate. In Inkscape at least, there are methods to use boolean operations to do something very similar to Illustrator's Shape Builder. It's a little more complex, but doesn't involve anything radical like having to redraw everything. [See my answer here](https://graphicdesign.stackexchange.com/a/116788/89608). It's also possible to join several open paths fairly easily, cut paths into pieces, rejoin others etc. No redrawing is required.


yml file syntax highlighting with Sublime Text

Question: How can I get proper syntax highlighting in yml files, such as users.yml with Sublime Text. As of now there is no highlighting, even erroneous things such as # symbols in string interpolation being treated as a commenting out hashtag.
Answer: There is currently a pull request to completely replace the old YAML syntax highlighting definition with a new one. I haven't tested it yet, so I don't know if your particular issue has been addressed, but you can certainly test it for yourself if you wish. Simply create a YAML folder in your Packages directory, and save the file I linked to in it as YAML.sublime-syntax. It should override the current syntax. All of this assumes, of course, that you've upgraded to build 3103 or are using the latest development build, otherwise the .sublime-syntax format won't be recognized by Sublime.


Deja-Dup Google Drive Support

Question: I tried to search to see if Google Drive is supported the same way Ubuntu One is supported for Deja-Dup but I haven't seen anything concrete. I don't want to store a local copy of the backed up files, but rather put it directly to the Google Drive account and prevent it from being sync'd.
Comment: Gdrive doesn't have official client for Linux, so I doubt a tool like that exists
Answer: You still cannot do so using deja-dup but fortunately it doesn't matter as you can use duplicity to achieve the same purpose. Deja-dup is the gui front-end for duplicity. You can use duplicity directly from the command line and surprisingly it is simpler than using the gui of deja-dup!
You need to install the package python-gdata first as it is not part of the base system.
sudo apt-get install python-gdata

After that you can use duplicity to put a local folder directly to google drive by issuing the following command:
duplicity localfolder gdocs://firstname.lastname@example.com/remotefolder

or
duplicity localfolder gdocs://username:firstname.lastname@example.com/remotefolder

In the second case it obviously won't ask for your gmail's password(but would still ask for the encryption passphrase).
Command to restore:
duplicity restore gdocs://email@example.com/remotefolder localfolder

In all the above cases localfolder is a folder in your home directory and you are running the commands from your home directory.
Two minor caveats. Firstly, while restoring you have to ensure that localfolder doesn't exist otherwise duplicity will abort saying localfolder already exists. Secondly, I have tested the above in ubuntu 14.04 so can't comment about the other versions.
Comment: This was hugely promising, but when trying it out, I get `BackendException: Error while authenticating client: Server responded to ClientLogin request: 404, https://developers.google.com/accounts/docs/AuthForInstalledApps` error, pointing out to a complaint of old authentication method. Is there any updated procedure on how to use `duplicity` with [OAuth 2.0](https://developers.google.com/identity/protocols/OAuth2)?
Comment: If you install the command line google "drive"  software, you execute a command "drive push " to upload your files without a password.  So you should be able to do that in your shell file.
Answer: The only solution I have come up with is to back up to a local drive using Deja Dup, then zip the folder and upload to Google Drive.
I am hoping to find a way to create a folder with Google Cloud or Google Drive and achieve incremental backups automatically.
Currently I get the error:
Cannot resolve hostname when using //drive.google.com/

Answer: This was reported in this bug, for which a fix has been committed. The change should be included in version 32.
Update: The fix was reverted due to issues with the duplicity backend. However, duplicity can still do this. There is a question on SO about how to get it working with Google's OAuth, at least with the Duply frontend as of December 2015. This involves installing pydrive, setting up access on your Google account, and creating a settings file for duplicity.
Related question with other options: Backup with duplicity on Google Cloud Storage

Deja-Dup Google Drive Support


First match in a collection

Question: I want to convert this code to a linq solution. What it does it looks into a collection of customers and see if at least one of the has a middle name. This code works fine, I'm just trying to learn linq, so looking for an alternative solution.:
//Customers - List<Customer>
private bool checkMiddleName()
{
    foreach (Customer i in Customers)
    {
        if (i.HasMiddleName == true)
        {
            return true;
        }
    }
    return false;
}

I tried to write something like: (Customers.Foreach(x=>x.HasMiddleName==true)...
but looks line it's not the method I'm looking for.
Comment: FYI -- the ForEach method on List just executes the given function on each member of the list
Answer: If you just want to know if theres at least one, you can use Enumerable.Any:
bool atLeastOneCustomerWithMiddleName = Customers.Any(c => c.HasMiddleName);

If you want to know the first matching customer, you can use Enumerable.First or Enumerable.FirstOrDefault to find the first customer with MiddleName==true:
var customer = Customers.FirstOrDefault(c => c.HasMiddleName);
if(customer != null)
{
    // there is at least one customer with HasMiddleName == true
}

First  throws an InvalidOperationException if the source sequence is empty, whereas FirstOrDefault returns null if there's no match.
Comment: Any way to return true or false from the query?
Answer: var result   = Customers.Where(x=>x.HasMiddleName == true).FirstOrDefault();

Answer: Based on this:

What it does it looks into a collection of customers and see if at least one of the has a middle name.

Try
return Customers.Where(x => x.HasMiddleName).Any();

This query return true if at least one custmer has the property HasMiddleName = true
Comment: `Any` takes a predicate, so you can shorten this to `return Customers.Any(x => x.HasMiddleName);`
Answer: You may use the following to achieve what you need:
Customers.Where(cust=> cust.HasMiddleName).Count > 0

So , if Count is more than zero means you have some customers who have Middle name.
Or for better performance you may say:
bool customerWithMiddleName;

foreach(Customer cust in Customers)
{
  if(cust.HasMiddleName)
  {
    customerWithMiddleName = true;
    break;
  }
}

Comment: This requires the code to count how many correct items there are, rather than short-circuiting the first time a match is found. It could be unnecessarily expensive. Better to use .Any().
Comment: That's not a good idea since it executes the whole query, only to know if there's one matching element. Consider that Customers contains 1000000 customers and the first has a middlename. `Any(cust=> cust.HasMiddleName)` would return `true` immediately whereas your approach would check each and every element before it returns.

First match in a collection


Expresso Store: User input Price

Question: My client would like to sell gift certificates, in addition to having set prices they want the user to be able to input their own price. Is it possible to have a store item without a price?
Answer: As Ian has mentioned Store does not currently have the ability for users to enter their own price in. On exp-resso.com there is a channel for the donations (tip jar) that has a single product with a value of $1. When a user enters the price that they want to donate they are actually just adding X amount of items to the cart at $1 a piece so a $25 donation is actually registered as 25 donation items of $1 for a total value of $25.
I wrote a blog post a while back that deals with a similar situation.
Answer: As far as I know it's not possible to enter a product without a price as price, along with SKU, are required fields. One option would be to make use of modifiers to make any number of variations possible (£5, £10, £15, £20, ...).
There is also provision in Store to accept donations. This does allow for a custom amount to be entered and an example can be seen at the bottom of the Exp-resso website. I've not setup a donations form before however so I'm not sure on the specifics of setup or how it is recorded in the sytem (if it's in with the orders or stored elsewhere). I'm sure one of the Store guys can help to clarify though.
Answer: There is now a Enable Dynamic Prices option for the field that should work.
See see this post for some help.

Expresso Store: User input Price


How to get total fees of a NFT transaction in cardano blockchain?

Question: Is there any api for to get transaction fees of the NFTs when buy or sold and does the transaction fees includes Royalty fees ?
Answer: There are several ways to get transaction information. The most known API provider is probably blockfrost.io, but there are others like tangocrypto.com, or api.koios.rest.
You'll need to know the transaction hash and will be able to query information like the spent transaction fee.
The transaction fee applies for using the network and is enforced on protocol level. The concept of royalties does not exist in the protocol. Hence, they are not part of the transaction fee.
DApps/marketplaces need to make sure to handle royalties themselves. You might be interested in reading the CIP 27 (Cardano Improvement Proposal) describing a community standard for royalties.
I'd suggest you check out this resource as it includes a lot of great information and links to start with: https://developers.cardano.org/docs/get-started


Scale car wrap template to actual size

Question: I have an Adobe AI template of a 2017 Ford F250 that is designed at 1:20 scale that I would like to scale up to its actual size. Is there a way I could scale the entire template so that it's size matches the exact size of the vehicle?
Comment: Why do you want to scale it to actual size?
Answer: Maybe. Guess it would depend upon the vehicle. Illustrator's maximum artboard size is 227" (roughly 18 feet), which may be too small for some vehicle sizes.
Merely Select All then scale.
Be aware though, working that large in AI can cause it to be terribly slow depending on the amount of detail you add to the artwork.
Most people work at 50% or even 25% of actual size if not smaller, especially in a vector application where size doesn't matter.

Scale car wrap template to actual size


Evading Mordack in his castle

Question: In King's Quest 5, in the final area of Mordack's castle, Mordack himself often shows up seemingly at random to deliver an instant Game Over in the form of Sith Lord-style death grip.  Despite the apparent unpredictability of it all, however, I've heard rumors that there are actually tells and signs that can be seen that can allow one to predict and evade him consistently.  Is this true?  What specifically are all the signs?
Comment: If memory serves right you can walk out of the room before the game over, not sure though since it has been over a decade since I played KQ5. Good to see some people actually still play point and click adventures :D +1 just for that!!
Comment: Aw well, half a point for trying. Rounded up is still 1 :D
Comment: @Kevin Actually, I don't, lol.  Game Grumps is doing an LP, and I've watched several other LPs and looked at TVTropes for it as well.  Never touched the game myself.
Answer: I don't know about predicting Mordack's appearance, but there are some things that will bring his attention to you, as well as the guardian's:

lingering in one room too long, besides his library
playing the organ in the downstairs hallway
allowing the cat Manannan to run away after seeing you

I don't think he ever appears in the dungeon or the kitchen - they're both below him.
I just replayed the game a while back. Seemed so much simpler than when I first played it!

Evading Mordack in his castle


Parenthesis in negative numbers on Pandas Styler object

Question: So I got a 3x3 dataframe that looks like this:
import pandas as pd
df = pd.DataFrame([[-232.3,43.1,"hre"],[-245.7,-943.7,"jtr"],[956.3,435.2,"fgjh"]], columns=list("ABC"))

And I'm styling it using:
df_stl = df.style.background_color(axis = None, subset = ["A", "B"], cmap = 'autumn')

I wanna be able to format the final dataframe values (on the Styler object created after all these methods) with parenthesis only on negative number, without losing the background colors.
So I want something like:

A
B
C

$(232.3)
43.1
"hre"

$(245.7)
$(943.7)
"jtr"

956.3
435.2
"fgjh"

I tried to add a .map(parent) after .background_color(), where 'parent' is something like this:
def parent(x):
    if(type(x) == float):
        if(x>=0):
            a - f"${x:.,0f}"
        else:
            a = f"$({abs(x):.,0f})"
       else:
        a = x
    return a

So, I tried this:
df_stl = df.style.background_color(axis = None, subset = ["A", "B"], cmap = 'autumn').map(parent)

But it returns a

'ValueError': Styles supplied as string must follow CSS rule formats, for exameple 'attr: val;'. '$ (232.3)' was given

I know that I can use .format({"A": "${:,.0f}"}) for each column, but I want to format conditionaly some columns after those style methods, keeping that and other methods that changes colors based on values. Is there any easy way to achieve that result?
Answer: The reason .map() is throwing an error is because that expects you to pass a function that returns CSS-styling, not a formatted string (see docs). E.g. something like background-color: 'red';
You can use your parent function in a .format() call though and that won't change the underlying data or colors. So that should allow you to apply your other conditions too. For example (with a slightly cleaner parent function):
def parent(x):
    if isinstance(x, float):
        return f"${x:,.0f}" if x >= 0 else f"$({abs(x):,.0f})"
    else:
        return x
df_stl = df.style.background_color(axis=None, subset=["A", "B"], cmap='autumn').format(parent)

Applying formatting to only a single column
[Update based on comments]
If you'd like to only apply your parent function to a single column, you can do this by instead passing a dictionary. Let's say you want to format column "A" with parent , you'd just do this:
df_stl = df.style.background_color(axis=None, subset=["A", "B"], cmap='autumn').format({"A": parent})

If you also wanted to style column "B" with other_style_function then just do
df_stl = df.style.background_color(axis=None, subset=["A", "B"], cmap='autumn').format({"A": parent, "B": other_style_function})


Performance of Numbers 3.0 for large calculation sheet

Question: When I used previous versions of Numbers to work with files containing a lot of large formulas, the performance of many actions were slow, including scrolling.  Can you comment how about the latest software update from Apple?
Answer: I just purchased and tried out Numbers 3.0, and Apple definitely improved the calculation process, as my sheets using large formulas already perform much faster. Performance is better.
Comment: You could mark your answer as accepted so that others can decide whether or not to look at this question.


Is using the toString() method an example of abstraction

Question: If abstraction is defined as hiding implementation details, then would that mean that calling the toString method is an example of abstraction?
Answer: In java, the root class Object has a default toString method, every sub class will inheritate this method(although usually it is overrided), it is an example of abstraction.
Answer: Yes.
Since toString is an instance method defined by Object class, its invocation is virtual. Hence, it hides the details of the behavior from the caller, making it an example of abstraction.
Answer: Abstraction means adding only those components in your design/code that are required by your application.
Hiding implementation details is encapsulation.

Implementing toString() is more an example of Encapsulation. Reasoning: The object decides what information about self, does it want to give to the output stream.

See this for detailed explanation.
Answer: Abstraction means, define relevant part of real world. You probably mix the typical OOP language keyword abstract, that is rather a declaration of interface. As wikipedia says:

Abstract types are useful in that they can be used to define and enforce a protocol; a set of operations that all objects implementing the protocol must support.

So it is an abstraction in terms of OOP principles, but every model of the real world you create, is an abstraction, so defining a class.
Hiding implementation details is rather part of the encapsulation.
Correct me, if I am wrong.


how could an alien species with modern technology communicate at long distances when their language is made up of sign language?

Question: Let's say that these aliens have recently sent up a manned satellite into their orbit. Let's say these aliens mainly speak through sign language. How will these alien astronauts communicate with those down on the surface?
Comment: I know it's hard to believe, but there was a time when we didn't have telephones and radiotelephony. Yet, somehow, people managed to communicate over long distances using an ancient art called *writing*. (And, hint, not all writing systems are linked to the sounds of the language; the Chinese do pretty well with a writing system which has very little linkage to the phonetic form of words.)
Comment: Are you saying that there is no written communication? And no video?
Comment: Would it be fair to alternatively phrase this question as: How would a species who communicates visually use radio or such to communicate when video hasn't been invented yet?
Comment: So you've never heard of semaphore, texting or video conferencing then?
Comment: I think the *real* question is how did they communicate while piloting things like fighters when their hands are busy at the controls and their eyes are busy looking out the cockpit, even if video and text had already been invented. Or how would any communication get done while doing anything for that matter. How appendages do these aliens have?
Comment: Maybe the question is more clear when you explicitly state that they don't have the bandwidth (yet) to broadcast video.
Comment: Upvote - "Television" was my first thought.   Although, is they can send someone into orbit, I would imagine that they would have TV - after all, it's sending bits by radio & assembling them into pictures at the receiver.
Comment: With the real-word example, video technology predates manned spaceflight by at least 30 years. In the absence of video technology (and written language), they'd send digital data which encodes a limited set of "signs" (words), enough for the sort of communication that is absolutely necessary. Though it's difficult to imagine spaceflight among a species with no written language.
Comment: @MawgsaysreinstateMonica Early video is absolutely not "sending bits". It was all analog.
Comment: @DKNguyen Soldiers often use a form of 1-handed sign language to communicate complex tactical orders so that they don't have to drop thier weapon to communicate.  Likewise, your space pilot could use a similar system to retain one hand on the controls.
Comment: First of all how they would achieve high technology level without a good way to transmit knowledge?
Comment: @JohnO Yup, I understand that. My point twas just that you are simply sending information. Encode, send, decode.  I din't care if it is analogue, like a radio signal, or digital liking a mirror. My point is that I think that the OP is confusing himself by thinking about "sign language", rather than "information"
Answer: The same way we are doing right now.
We humans technically communicate by sound and body language. In practice, though, many people communicate more by text and emojis than by voice nowadays.
If the aliens are smart enough to put stuff in orbit, they should be able to read, type, and select different kinds of reactions for every message they receive on whatever IM app they are using right now.
Comment: This. I find it deeply ironic that someone would ***write*** their question of "how would people communicate without talking?" :)
Comment: @Nosajimiki You've chosen a bad example there, because written English is equally hard for hearing people for the same reason!  Famously it has no good rules for what each letter corresponds to; or rather, it has dozens of rules for every letter and you won't know which should be used unless you already know how the word sounds.  That's why children and even adults almost always mispronounce words they've only seen written and never heard.  It is *not* a "phonetic character set" in any way. German mostly is, and so is Japanese (with hiragana/katakana), but English very much isn't.
Comment: @Renan I would say you just proved my point.  I can still interpret your meaning despite improper spellings by sounding it out.  But to most deaf people, that sentence might as well be an SSL key.  I agree that English is not perfectly phonetic, though.
Comment: @Graham Yes, but they wrote it using a phonetic character set.  Learning to read and write in English is comparatively really hard for deaf people because they have no reference points for what the letter correspond to.  For deaf people, learning to write in a phonetic language is just about as hard as learning a pictographic language.
Comment: @Renan: Depending on dialect, that actually might be an accurate representation of some person's speech.  Which is why English's not-really-phonetic nature makes it better for communication.  E.g. I understand what a "clerk" is when a British person writes it, but might not understand their pronounciation as "clark".
Comment: Yes it is full of irregularities, sure, but still phonetic.  A 5 year old kid can still see a new word and sound it out well enough to figure out what it is 95% of the time or spell it close enough to right for people to be able to tell what she was trying to write, even if it's wrong.  If you are deaf though, (especially if you are not raised around speaking people to know how to read lips), you often don't even know what words are supposed to sound like. There is no way of knowing that an inward facing open hand with fingers together that arcs down and away from your chin is spelled g-o-o-d.
Comment: @nosajimiki u shuld lesten to wat Graham sad, hes rite (if English had a purely phonetic alphabet I wouldn't be able to write like that while still sounding right).
Comment: @nosajimiki ... now that I look at it, you're right.
Answer: Signwriting.
In recent years people who use sign language have invented thier own writing system called signwriting.  It is a written system of annotating sign gestures instead of phonemes which makes learning to read and write much easier for people who can not hear to be able to correlate sounds with a Phoenician based alphabet.  Instead, all of the characters are meant to represent what you do with your body to sign.  This way, a child who knows a sign language such as ASL can make informed guesses about how to read and write with the words they already know.
I don't believe a standardized signwriting keyboard exists yet, but presumably, you could develop a system that divides each gesture into somatic components such as facial expression hand actions, directions, transitions, etc. such that typing a series of keystrokes could be used to compile a full body gesture.
Once you establish a system of compiling words from thier simpler components, you can encode these components into a character set and store/send/receive writing just as efficiently as we can with English.
https://www.yumpu.com/en/document/read/12261249/learn-to-read-american-sign-language-in-signwriting-goldilocks
That said, broadcast TV was invented in 1928 before the space race began; so, your people will probably be able to radio broadcast video for expressing sign language even if they don't have a convenient system of converting written language into a digitalized written system yet. Recording it though would not be cheap. In 1961 when Yuri became the first man in space, video tapes costed about 3000 dollars per hour of film (when adjusted for inflation); so, there would be good reason to develop a written system in lue of just recording everything.  Storing written language is about 2.25 million times more efficient than an uncompressed 640x360 RGB 30 fps video without an audio track.  Even with modern digital computerized compression techniques, text is still on average 40,000 times as efficient; so, text is still often considered the preffered way of archiving and transmitting large amounts of information.
Answer: Assuming a visual feed of some kind if available, use that. If not, use a Morse-Code equivalent to represent the correct signs. If it's letter-based, i.e. the sign alphabet, this will be relatively simple; if it's not based on letter but rather uses unique signs for every word, this will be very difficult and thus worth looking into a constructed language of some kind to solve.
Answer: Via Translations
Morse code isn't exactly easy to comprehend but it was used as a simple means of communication to be translated. Your aliens would need a non visual way of sending information that could be translated back into signing for general communication.
Comment: Morse code is every bit as easy to understand as the Latin alphabet, Kanji, or musical staff. That is, incomprehensible, unless you have been taught to understand it. Then it's easy.
Comment: In addition to --- -∙∙∙'s  excellent observation, Morse Code  is *spelling*, rather than *saying* and (once you get your 'ear in' for the patterns) can be just as fast as spelling the words out with the Phonetic Alphabet.
Comment: Fine, maybe I have problems with Morse, either way rather than complicated hard to send gestures, the auditory/visual equivalent of binary is superior for sending information long distances.
Answer: Right now the only thing we have in real-life that handles this is humans using sign language. I think this is the wrong model, because the idea is that an entire species is using sign language.
I can only guess at some of the evolutionary traits that make sign language better for these beings than voice. However, I'd like to state that sign language has some serious deficiencies when compared with simple vocal communication (yells, howls, and screams). For one thing, sign language is a short-range communication. It doesn't cover the case where somebody screams for help from a distance away. It might not even cover the case where somebody yells "Duck!" to get people to drop to the ground. For some things being deaf is worse than being blind.
Why would these beings using sign language rather than voice, and how could this be made more advantageous?
My suggestion is that these beings have at least a minimum hearing/vocalization organs for emergencies. Perhaps they have little control over the range of noises they can make, but they can use this to get others' attention.
One thing I suggest is that they have more dispersed eyesight than humans. Perhaps they have more than two eye-stalks. This would be useful when in conversation with another being and still continuing with whatever they are doing (typing, driving, etc.) They would also need at least two hands, perhaps more, for conversing.
As they raise in technology, they would develop some form of writing, to pass on information, or to communicate over long distances. This could become, as it has here on Earth, a form of electric/electronic communication. Eventually they would have computers, and need to communicate with them.
So I see that the alien station-keepers would use typing, and orbit-to-planet email. Eventually, they would have the technology and bandwidth to communicate visually, and use that for communication. They'd probably develop their own TentacleTube for sharing visuals to all other such beings.
Answer: Working with the premise of someone in orbit communicating in real time with someone on the ground, then they can't reasonably be sending physical written communications back and forth. However for a species to advance to the point of putting someone in orbit, they almost certainly need to have a writing system established (that's a huge part of what allows education and building on the discoveries of ancestors).
But then the existence of written language brings up an important point - someone had to develop a convention to express concepts as patterns of physical marks, which aren't the same as their normal sign-language. Whether you say it's based on individual symbols representing whole concepts/words (pictographs and such) or by multiple symbols being put together to have meaning (an alphabet of some sort), something of that nature would exist.
Once that idea exists, it's not a stretch for them to invent other conventions to convey concepts/words/language using other mediums than physical marks.
On way would be using very simple radio technology, one can send pulses of different lengths and thus have an equivalent of Morse Code. But if they have put someone in orbit, then they can presumably do more than just that with radio. Different frequencies and amplitudes can be used to encode information much more densely than Morse Code.
But what exactly might it be like, well that depends.
I presume they don't have a biology of effectively making sounds, but can they still hear? Then radio waves being heard by the receiving person as beeps or some other easily distinguishable sounds is a reasonable idea.
What if they don't have hearing? Then perhaps they decode the signals as blinking lights. Morse Code could work just as well if a person watches a light on their receiving device. Or if one presumes something a bit more sophisticated, then it could be an array of colored lights or perhaps a grid of lights (2x2, 3x3, etc) where each light responds to a different frequency/amplitude in the radio waves and then the receiving person interprets those patterns according to the established convention.
Answer: How about with a pantograph over a radio link.
A pantograph is a device to transfer a mechanical motion from point A to point B.  One classic use is for a mass-signing machine.  (Sign one document, make 100 copies of your signature.)
They can then be built powered and electronically controlled.  We call this a "waldo" or "remote manipulator".
So, your aliens could develop a waldo system where one person wears something akin to gloves and a phone line equivalent transfers their motion to a remote viewer.  The remote end would probably have mock hands (or other manipulative organ) with a arm-like sleeves over the works.
Once this telephone-analog is achieved, probably well before space flight, one need only change it to use a radio link to make it space viable.
Answer: The orbiting satellite can use a mirror to reflect sunlight down to the surface. Without a writing system, they must have tremendous memorization ability and the ability to detect fast movement. Otherwise, the amount of information needed to transmit technical information would take too long. Therefore, a mirror (or a set of mirror) would answer the question as posed.
Answer: The short answer is that their communication would depend substantially on their writing scheme.  Like in our technology, the written message is transmitted first, because it is far easier to transmit than anything analog like spoken language.
The more interesting longer question involves the nature of their language.  Sign language is not just a series of concrete signs.  It conveys a great deal of emotive content in how you present the signs.  Many who know sign languages lament how hard it is to convey what they really want to say in English because it lacks the subtle nuances they are used to having in their gestures.
So the fun question is what sort of a society might be built up around such a nuanced language.  How might they differ from us?  The answers to that question would materially affect the nature of their written language, and thus their communications here.


Swapping G8 Halogen Under-cabinet fixtures for LED

Question: I've got 6 under-cabinet fixtures that use G8 20V bulbs. I'd like to swap them for LEDs. I've tried putting in bulbs but there's some difference in the voltage load and there's a lot of flickering. So my next step I guess is to swap the fixtures. They're direct wired around the perimeter of the kitchen, controlled by a switch. Should I expect this to be somewhat straight forward (is anything? :-) )? Should I expect there to be more to swapping one for the other than connecting the new one up to where the old one was, moving the old fixture wire connection to the new fixture wire connection? I haven't opened one up yet but I assumed the fixture is connected to the wires in the wall via some wire nut or similar.
Comment: Some of those supplies give a 20V AC output not DC which may cause the flickering...
Comment: It's quite likely the voltage is AC.  You will need LED bulbs that play nicely with AC; that's not hugely complicated but it does add a nickel to the manufacturing cost. So J random cheapie/dollar store/Amazon Marketplace/ebay bulbs may not have that feature.
Comment: @Harper-ReinstateMonica probably easier to fit a rectifier...
Answer: Are you correct in the questions?  Should it be G8 20 watts not 20V.
To replace the G8 20 Watt/120v build it is a direct straight replacement.  Since you did do the swap, but it is flicking, there could be two issues

The replacement LEDs were not dimmerable and you have a dinner in the switch
The replacements are dimmerable, but the dimmer is not rated for LED bulbs.


Can a miner gain an advantage by not including any transactions in their block?

Question: If searching for the correct nonce can only be done once the world state has been computed, it would seem that if miners include no transactions in their blocks, they could begin searching for the nonce before those that do. As long as there is a fixed reward per block, this would be profitable. What is there in place to prevent miners from doing this? Relatedly, how do miners decide when to stop accepting transactions and start searching for the nonce? Even if miners are acting in good faith, they would still be penalized by accepting more transactions than their peers.
Answer: If there are transactions available to be included, there are no advantages in not including them, as miners earn fees from transactions.
If there are no transactions available long enough that a miner managed to mine a block without transactions, we can say they would have gained an advantage against miners that decided to stay idle an wait for new transactions (assuming block reward > mining costs of course).
Let's say for the sake of argument there were no transactions for an entire day, so Miner A decided to keep mining, but Miner B decided to wait for transactions. They have the same hashrate, same energy/hardware costs.
One day passes, and now the network got a bunch of transactions. Miner B begins mining, and now Miner A has two options:

Include transactions in the hash function (reset the nonce).
Ignore new transactions, continue mining from where they are (less nonces to check).

In this scenario, option 2 would seem to be more advantageous because you're not resetting the nonce, right?
Well, that only holds true if, and only if, the golden hash is guaranteed to be found in the remaining available nonces from Miner A, without resetting any inputs. As soon as Miner A has to change any other inputs, this advantage of starting "earlier" is lost. That would be the case if:

They ran out of nonces and couldn't find the target hash, so they need to change some other input (e.g. timestamp, transactions) to keep trying;
A new block was mined by Miner C, essentially forcing them to update the previous_hash which is used as input in the hash function of next block.

If Miner A ever founds themselves in this situation where changing any inputs is required, then there is no point in keep ignoring the new available transactions.

If you are interested to know why some blocks may have no transactions, it's not really because miners are looking for advantage, check this answer.


Etale $K$ theory coincides with algebraic one in high enough degrees

Question: I have seen the claim that Beilinson Lichtenbaum implies that higher algebraic $K$ groups coincides with etale ones integrally in high enough degrees. Is this statement accurate? What conditions are required and how to derive it?
Answer: To my knowledge the most general known statement has been proven by Clausen and Mathew in their paper Hyperdescent and étale K-theory as Theorem 1.2. The precise conditions on your commutative ring (or more generally algebraic space) are a bit technical to summarize, but are very general and give explicit bounds. Away from the residue chacteristics one can apply the Voevodsky-Rost norm residue theorem and at the residue characteristics they manage to apply a reduction to topological cyclic homology ($TC$). I recommend looking at their paper for a more detailed explanation.
Comment: This is in a sense actually easier on the derived level (in this case in the setting of spectra). There, $p$-completion is localization with respect to $\mathbb{S}/p$ and rationalization with respect to $\mathbb{S} \otimes \mathbb{Q}$. If a map is an equivalence after $p$-completion, its cofiber is $\mathbb{S}/p$-acyclic and hence $p$ acts invertibly. If this is true for all $p$ and the cofiber vanishes after tensoring with $\mathbb{Q}$, it must be zero itself.
Comment: I see, one need to prove it for different primes and then rationally. This might be a silly question does this imply that the groups are integrally isomorphic? I am a little bit fuzzy on group theory but I can see how this implies integral isomorphism with the finite generation assumption on the groups but that might not be necessary.
Comment: Sorry another question. The conditions seem to be some sort of bound on the Galois cohomological dimension of the residue fields. Do you know if one has such a bound only in mod $l$ Galois cohomology (base field is char 0) does that imply that such an isomorphism holds in high degrees for mod-$l$, $K$-theories?


How do I make this concave shape?

Question: So i have a disk to make for my dad. He wants to buy a 3d printer and i need to make this shape. I have looked every where over the internet and couldn't find a tutorial to make a shape like this one. Can anyone help me?
Comment: this is like a cylinder, you need to scale its edges so that it gets thiner towards the bottom, what difficulty have you met?
Comment: yeah, show us what you tried so far. This is not a "we do all the work for you"-platform, but a "we help you with what you made so far"-platform.
Comment: https://blender.stackexchange.com/questions/111986/simple-way-to-create-a-curved-tunnel-between-two-planes/112004#112004
Comment: Sorry I haven't been on the pc for a few days. I was thinking i could make a cylinder to make the base and the make an uv sphere, then i used the boolean modifier but it didn't look like the picture from above
Answer: Welcome on the forums, to get you started...
I used a modifier to spiral a curve line
next added a modifier to make it solid
next added 4 cylinders by mirroring one.
next i did a boolean operation to subtract the 4 cylinders.
for visibility i altered the 4 cylinders so you see them as wire frame.

Note you can change this file, the modifiers, or in edit mode change the curve or the cylinders.
Comment: nice work!!!!!!
Comment: nice work but i tried doing the same thing you did and its looking not even close to what you did.
Comment: its probaply because of the settings I used to have more in betweens than the default for the spiral.modifier

How do I make this concave shape?


Xetex on Texlipse

Question: I want to enable the use of unicode text in my latex files. How can I compile using Xetex in Texlipse? I can't seem to find the option to select which builder to use like in other IDEs.
Comment: Here is my first google result for *texlipse builder*: http://texlipse.sourceforge.net/manual/configuration.html
Comment: I don't see Xetex though.
Comment: You should look if your distribution of choice has XeTeX included. If yes, look for how you can use Xe(La)TeX with it, as in: http://sourceforge.net/p/texlipse/discussion/search/?q=xetex
Comment: I think I need to say I am only answering because nobody else does. There are certainly way more proficient TeX-users  out there who must have run into this problem and most likely solved it.
Answer: I personally don't know what the difference between XeTeX and XeLaTeX are, when I looked into it on the sourceforge discussion page linked in the comments above there is a question that configures hyperref for xetex and explicitly states the pdfcreator as xelatex.  Additionlly, the Wikipedia page for XeTeX provides a source example which explicity refers to XeLaTeX.
But in terms of setting up a command line builder I can comment:

I don't think xetex can be configured from (Window > Preferences > Texlipse > Builder Settings: because each of the listed programs correspond to a specific class file (see list of classes on the left hand side of the image below) within net.sourceforge.texlipse.builder of net.sourceforge.texlipse_10500.0.2.b201407171807E43sw.jar (found in your plugins folder of the eclipse installation)
On my computer any of the missing command line paths shown in the right hand side of the picture below as () have not yet been installed.

If xetex was to be added to this page, it would probably be done within the source/development of the plugin itself.  I don't have any experience in eclipse plugin development and can't comment on whether you could easily create a class file to point to xetex.
That being said, Eclipse can setup external programs as builders from within the Launch Configurations.  Using eclipse variables with the command line inside this setup is easy and works very well, but it is still recognized as an external program so automatic building requires some editing to use the right program.
I find sequencing multiple programs in the builder menu or launch configurations cumbersome and not very stable so I write batch file scripts and set them up once in the external programs
Comment: Concerning the difference between XeTeX and XeLaTeX, these are both formats (TeX and LaTeX, respectively) that use the `xetex` engine.  See [this answer](http://tex.stackexchange.com/a/151731/17423) for more information.

Xetex on Texlipse


Identify vintage negative 50 x 60 mm image on 70 mm wide filmstock

Question: Trying to determine what film size these old negatives are. The filmstock width is 2-3/4" (70 mm). There are no sprocket holes. The image size is 2" x 2-3/8" (50 mm x 60mm). I have run across some old negatives in both color and black and white. The images appear to be circa 1950s.
Answer: In that era, many firms engaged in "school" business. They bid on the task of making school year books making group pictures and senior portraits. They used custom roll film cameras made by Beattie, Camerz (Photo Control), and Nord Photo Enginering, and others. Kodak 70mm film was commonly used in color and black & white.
It was big business. I worked for Nord, we also made special "package printers". These printers made up the packages that contained sets of multiple sizes. A typical package was 1 5x7  -- 2 3 1/2 X 5 -- 4 wallets and 16 postage stamp size pictures.
These cameras were loaded with 70mm, or 46mm or 35mm film in 100 ft. rolls.
Comment: Alan Marcus, thanks for the reponse!
Answer: 116 and 616 format were also 70mm wide and unperforated.
The Kodak Brownie Jr 6-16 and Kodak Target 6-16 both used 616 format film.

The last cameras made to shoot 616 were produced in 1948, but existing stocks sold well into the early 1950s. The film was made until 1984.
Comment: Thanks Michael C for your input. I do remember using 616 film in an old Brownie when I was a kid. In fact I found some 616 in this old box of negatives that had images measuring 2.5" x 4.25" which scanned very well.


Removing Picklist items from multiple record types

Question: Is there a way of removing picklist items from multiple record types in one go, just as there is a way of adding picklist values to an object with multiple record types.
For example I have ObjectA__c and I have a picklist called PicklistA__c I also have two record types for ObjectA__c called RecordTypeA and RecordTypeB. When I add an item to the picklist PicklistA__c for Object__c I get the option to select which recordtype I want to add the picklist value to. However when I want to remove the picklist value from certain record types I can only do this by going to the picklist field PickListA__c on the individual record type and removing it.
Answer: I think that the faster way is to edit the Object__c.object.
There you'll find the RecordTypeB definition where all the PicklistA__c related values are.
By removing the values you don't want within the RecordType definition and save the file your task will be done.


Play by post mapping system

Question: I'm looking for a means of having a battle map and tokens for a play by post game. Something that doesn't require anyone, except maybe the DM, to download software, and functions perfectly well, even if the whole party isn't online at once. Would you know of such a thing?
Answer: Roll20 does that really well, using only your browser.
You can use character sheets of many systems, and move tokens. You can restrict access for modifying or seeing token/sheet/handout player by player (or all at once), roll dices on the chat (to prevent cheating), use a fog of war, have several map (but only one at a time is show to the players), ...
The campaign is save on a server and anyone with the link (and account) can view it at anytime, with or without other players. So in your case, your players will be able to see the map and fill they character sheet whether you're online or not.
It's a really powerful tool and free, but you have to create an account (take about 5min max) and since it's powerful, it require to fool around a bit to understand how it works. That said, I've only watch the basic tutorial and guessed the rest through testing and I'm doing well.
Comment: Yes, anyone who have the link can access the game at anytime, with or without other players. It's very useful for the GM to prepare the next campaign/session/encounter, and to all player in your case. I'll edit my answer.
Comment: Is it possible to use roll20 without everyone being online at the same time/without the GM being online?
Comment: You are right; just checked to see if I could access the map we used last night and I could.
Answer: You can use any map software (like Maptools or Photoshop) to create the maps on your side, including token positioning, then upload the result image to an external site (like Imgur) and use the [img] tag that is allowed in most php forums.
A player can post something like "I will move 1 square in the NE direction and attack the monster", and when the DM gives him the result of his action, the DM can move the token in his personal file and post the new image. That requires only the DM to have access to the image file.
Answer: When you say, "play by post", I assume you mean a forum-based game rather than a snail mail game, and that all players will have access to a web browser even though they may not be able to be online at the same time and may not be able to install software where they play. Given these conditions, I recommend...
Google Draw
It provides a good set of drawing tools, suitable for game mapping, and allows varying levels of protection. Need a world map exposed only as players discover new places? Share a map as a read-only drawing. Need them to move tokens for their turns? Share a map as an editable drawing.
I have used this to share maps and diagrams with remote players, albeit synchronously. However, my edits were done async and players referred to maps in between games.
This solution provides advantages over just emailing pictures - or links to static pictures posted in  a forum - to people as the current version is always available. If you ever want to "freeze" a map at a given state for historical purposes, you can just make a copy.
No one involved will need anything besides a modern web browser.
Answer: Use an online spreadsheet. Format the cells to be squares, use colours to indicate terrain, and letters or words to tell where the goblins and player characters are. If you trust the players to not mess up or cheat (and you presumably do, since you play with them), you can give them editing privileges so they can make their own moves. Or you can have the players communicate to you and edit the spreadsheet by yourself.

Play by post mapping system


Can I add menu on other android application?

Question: I want to add menu on other android application . For example , the user snaps photo with android phone. When user select option menu to save, I want to add this opiton menu on my project menu .Is it possible ?
Answer: No you cannot alter/add the behavior of other android application unless you go ahead and customize the ROM.
What you can do though for your case is to create an application that allows user to capture picture using Android camera Intent. Once the image returns to your application you can show your options menu. The other approach would be to create a custom Camera application.


What is the impact of deleting an answer or question on reputation?

Question: What happens to reputation gained\lost from that question or answer?
Answer: When  a post is deleted, it no longer counts towards your reputation: that includes both up votes and down votes.
However, reputation is cached, and any reputation changes will not reflect in your total until your reputation is manually recalculated. This can occur from:

You manually doing it yourself by going to the reputation page and pressing the Trigger Reputation Recalc button
A moderator or Stack Exchange employee doing it, generally as part of other action done to your account (think suspension)
A global recalculation, usually due to some major change in how reputation is handled. This is extremely rare: once or year or less.
Comment: Same with migrated questions. A rep recalc will remove any rep gained / lost on answers on questions that got migrated, but of course that rep will exist wherever the question got migrated. Downvotes on questions that migrate don't follow them though, kind of a fresh start.
Comment: I just magically lost 150 rep from questions getting deleted... it was definitely jarring. Is there an explanation of the reasoning behind this policy somewhere?