proposition: Fact mb_is_tuple_in_dec r n (v : vec _ n) : { r ∋ ⦉v⦊ } + { ~ r ∋ ⦉v⦊ }.
proof: Proof. Proof using Xfin Rdec. apply (fol_quant_sem_dec fol_ex); auto; intro. apply (fol_bin_sem_dec fol_conj); auto. Qed.
imports: List Arith Nat Lia Max Wellfounded Coq.Setoids.Setoid Undecidability.Shared.Libs.DLW.Utils(utils_tac utils_list finite) Undecidability.Shared.Libs.DLW.Vec(pos vec) Undecidability.FOL.TRAKHTENBROT(notations fol_ops fo_sig fo_terms fo_logic)