proposition: Lemma hcancelPtT A1 A2 x (v1 : A1) (v2 : A2) : valid (x :-> v1) -> x :-> v1 = x :-> v2 -> A1 = A2.
proof: Proof. by move=>V /(cancelPt V)/dyn_injT. Qed.
imports: Coq(ssreflect ssrbool ssrfun Eqdep) mathcomp(ssrnat eqtype seq path) pcm(options axioms finmap) pcm(pcm unionmap)