Agreed, i'm not sure whether one letter (immutable) greek variables are better than proper named variables.
Another consideration: A formal rule based math syntax could be checked by a computer (theorem prover).
Another consideration: A formal rule based math syntax could be checked by a computer (theorem prover).
Keep in mind we use special single letter variables all the time, sometimes multiple for the same concept. Multiply, divide, add, subtract. You learned them all in early education along with everyone else, and now you have a universal set of symbols to express arithmetic concepts.
Would we be better off if every occurrence of '+' was replaced with 'sum'? I don't think so, but that doesn't necessarily mean that loading up with single letter variables that people aren't familiar with is better. It's entirely to do with how familiar the target audience is with them. A library targeted for use by scientists might see benefit to more of them, while one targeted towards being accissible to many people might not.
If you stick to convention and use stuff like A for array, i for index, r for root, δ for small change (a delta), ε for error, Σ (Greek S) for sum, Π (Greek P) for product, etc.
It's only when you start using variable names as if they were free variables when they really aren't that you get into trouble with comprehension, especially from people not in your field.