proposition: Lemma domE K C V1 V2 (U1 : @union_map_class K C V1) (U2 : @union_map_class K C V2) (f1 : U1) (f2 : U2) : dom f1 =i dom f2 <-> dom f1 = dom f2.
proof: Proof. by split=>[|->] //; apply/ord_sorted_eq/sorted_dom/sorted_dom. Qed.
imports: Coq(ssreflect ssrbool ssrfun) mathcomp(ssrnat eqtype seq path bigop) pcm(options prelude finmap seqperm pred seqext) pcm(pcm morphism)