fact: Definition setf V (f : {fmap K -> V}) (k0 : K) (v0 : V) : {fmap K -> V} := [fmap k : k0 |` domf f => if val k == k0 then v0 else odflt v0 (fnd f (val k))].
imports: HB(structures) mathcomp(ssreflect ssrbool ssrnat eqtype ssrfun seq) mathcomp(choice path finset finfun fintype bigop)