name?

Stream: general

[Yury G. Kudryashov]

How should I name these lemmas? It should be something with gcd_add_left/right but I need 4 of them:

import data.nat.gcd
open nat

variables (m n : nat)
example : gcd (m + n) n = gcd m n := sorry
example : gcd (m + n) m = gcd n m := sorry
example : gcd m (m + n) = gcd m n := sorry
example : gcd n (m + n) = gcd n m := sorry

[Mario Carneiro]

gcd_add_self_left/gcd_self_add_left/gcd_self_add_right/gcd_add_self_right