perhaps true (maybe). but if the variables were named properly we would at least have a decent idea of what the expressions actually are - even if we can't then infer what they are for from that information.
imo that is precisely what a comment is for - explaining an algorithm or things that look unusual, not merely explaining what a variable is - which imo is precisely what a variable name is for.
Is there something wrong with code that is too dense to be self-documenting, especially if you're willing to write and distribute a paper to explain it? Would you understand "pivot" in quicksort if you hadn't read a description of how quicksort works?
Single letter variables with subscript are standard in math, and using short names makes the equations easier to see.