proposition: Lemma domeq2DE (f1 : U1) (f2 : U2) : dom_eq2 f1 f2 -> dom f1 = dom f2.
proof: Proof. by case/domeq2P. Qed.
imports: Coq(ssreflect ssrbool ssrfun) mathcomp(ssrnat eqtype seq path bigop) pcm(options prelude finmap seqperm pred seqext) pcm(pcm morphism)