proposition: Lemma big_pred0_eq (r : seq I) F : \big[op/idx]_(i <- r | false) F i = idx.
proof: Proof. by rewrite big_hasC // has_pred0. Qed.
imports: HB(structures) mathcomp(ssreflect ssrbool ssrfun eqtype ssrnat seq path) mathcomp(div fintype tuple finfun)