No, he’s right. “For any odd prime” is a not-unheard-of expression. It is usually to rule out 2 as a trivial case which may need to be handled separately.
It’s not unheard of no, but if you have to rule out two for some reason it’s because of some other arbitrary choice. In the first instance (haven’t yet looked at the second and third one) it has to do with the fact that a sum of “two” was chosen arbitrary. You can come up with other things that requires you to exclude primes up to five.
No, he’s right. “For any odd prime” is a not-unheard-of expression. It is usually to rule out 2 as a trivial case which may need to be handled separately.
https://en.wikipedia.org/wiki/Fermat's_theorem_on_sums_of_two_squares
https://www.jstor.org/stable/2047029
https://www.jstor.org/stable/2374361
It’s not unheard of no, but if you have to rule out two for some reason it’s because of some other arbitrary choice. In the first instance (haven’t yet looked at the second and third one) it has to do with the fact that a sum of “two” was chosen arbitrary. You can come up with other things that requires you to exclude primes up to five.