proposition: Lemma FinfunK : cancel Finfun fgraph.
proof: Proof. by move=> G; apply/eq_from_tnth=> i; rewrite tnth_fgraph ffunE enum_valK. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(fintype tuple)