N `{Naturals N} N2 `{Naturals N2} x : naturals_to_semiring N2 N (naturals_to_semiring N N2 x) = x. Proof. change (Compose (naturals_to_semiring N2 N) (naturals_to_semiring N N2) x = id x). apply to_semiring_unique_alt;apply _. Qed.
Require Import Require Import Import SemiRings.