This code will be read many more times than it is written, and anyone auditing its correctness will be comparing against the spec.
If the variables are spelt out, then you have to do the mental (or otherwise) translation before you can compare the two, adding overhead. For comparing the symbols visually, you don't even need to know their names.
Well, no, this was the main issue with homograph attacks in domain names [1] that brought us to the use of punycode in browsers [2]
In particular for a cryptographic library, I wouldn't want to constantly have to watch out for sneaky malicious variables put in the right place (e.g. try to compare visually the Cyrillic а, с, е, о, р, х, у with the ascii a, c, e, o, p, x, y (no, they're not the same characters).
EDIT: I realize that many programming languages today allow the use of unicode variables and I like that it's a possibility, it's just not the best when you need to be paranoid about the code
- [1] https://en.wikipedia.org/wiki/IDN_homograph_attack - [2] https://en.wikipedia.org/wiki/Punycode
I'm as proud of my heritage as the next Greek-American, but just because mathematicians use unintelligible symbols in their manuscripts doesn't mean we have do the same thing in code. Let's prioritize comprehensibility and give variables meaningful names, instead.