`{Integers Z} `{IsCRing R} (f g: Z -> R) `{!IsSemiRingPreserving f} `{!IsSemiRingPreserving g} x : f x = g x. Proof. rewrite (to_ring_unique f), (to_ring_unique g);reflexivity. Qed.
Require Import Require Import Import NatPair.Instances.