Every math paper I've read and written have written out definitions for all the notation they use, even have a section called "notations". Don't you read math papers? Or do you mean applied math papers? Applied math is more like engineering though so they get sloppier with notation, I guess the same thing happens when computer scientists do maths.

But that isn't really a problem with math, but a problem with sloppy people. Or you just didn't read the notation sections explaining everything.