proposition: Lemma big_pred0 r (P : pred I) F : P =1 xpred0 -> \big[op/idx]_(i <- r | P i) F i = idx.
proof: Proof. by move/eq_bigl->; apply: big_pred0_eq. Qed.
imports: HB(structures) mathcomp(ssreflect ssrbool ssrfun eqtype ssrnat seq path) mathcomp(div fintype tuple finfun)