proposition: Lemma indom_of_binds : forall A `{Inhab B} (M:map A B) x v, binds M x v -> x \indom M.
proof: Proof. Proof using. introv IB K. rewrite* (@binds_eq_indom_read A B IB) in K. Qed.
imports: TLC(LibTactics LibLogic LibReflect LibOption LibRelation LibLogic LibOperation LibEpsilon LibMonoid LibSet)