proposition: Lemma finsupp0 : finsupp [fsfun for default] = fset0.
proof: Proof. by apply/fsetP => x; rewrite !inE mem_finsupp fsfunE eqxx. Qed.
imports: HB(structures) mathcomp(ssreflect ssrbool ssrnat eqtype ssrfun seq) mathcomp(choice path finset finfun fintype bigop)