You realize that there are fairly standard single letter variables in programming, for which people are supposed to understand the type of the object, right?

I see a lot of 'n' for a number, 'i', 'j', 'k' for loop indexes, 'a' and 'b' for the variables in a swap function, 'f' and 'g' for various things involving function composition.

The case of knowing what a capital pi or sigma means, however, is much more like knowing what a "while" loop is.