fact: Fixpoint oeval a ks f z0 := if ks is k :: ks' then oeval a ks' f (if find k f is Some v then a z0 k v else z0) else z0.
imports: Coq(ssreflect ssrbool ssrfun) mathcomp(ssrnat eqtype seq path bigop) pcm(options prelude finmap seqperm pred seqext) pcm(pcm morphism)