Is there a way to improve the readability of equations in research papers? I read a lot of computer science papers, and have to understand a lot of equations. Most of the time the concept is so easy, that someone could explain it to me in 5 minutes. I one the other hand need up to an hour to get it.

It is difficult for me to search for the variables in the text, and often I print the paper out and write the meanings of each variable down on the side.

My questions:

So why is it not common to make equations and algorithms more readable? 

Is there some PDF reader plugin which highlights the variables in text? 
Any tips on how to improve in reading such papers?

Why do authors not add an additional list to each equation with a list and explanation of each variable. Should I do that?
I do not believe that the problem is fundamentally about space, but rather is a cultural problem that stems from three things:


Reviewers do not demand clarity in their mathematics
There is often a perception that "fancy" or "difficult" math means more important science (related to #1)
Really clear presentation of mathematics is difficult and takes a lot of work
("I would have written a shorter letter, but I did not have the time.")


Ultimately, a community tends to get what it rewards.  There is no reason that math must be impenetrable.  Even if one is faced with a space problem, you can play the same sort of games that you do with figures and data in order to fit.  Right now, however, it is typically understood and accepted that you don't have to do that with your mathematics.  In fact, some scientific communities will punish a researcher for presenting mathematics more clearly, because it makes the work look "less significant."

Technology cannot help solve this, because ultimately it is a problem of human communication.  Anyone who is bothered by mathematical impenetrability can, however, take their own small steps towards changing this culture:

In your own work:


Include tables and clear explanations in your papers.
Use as few symbols as possible, and choose the symbols to improve clarity, e.g., matching the symbol to the first letter of its description.
Buffer your equations with explanatory prose that restates their content in plain English.


When considering other people's work:


Call out mathematical impenetrability as a reviewer
Ask for tables, clear prose, etc. in the papers that you review
View the mathematical impenetrability of a work as a flaw rather than a good thing.


This is a very difficult problem, and unlikely to change any time soon, but it can be made better one paper at a time.  Moreover, it is my belief (and experience), that clearer mathematics can make for a higher impact and better cited paper, so it will likely be valuable to you in the short term as well, unless you are in a community that has a toxic relationship to mathematical impenetrability.