proposition: Fact Σ_fin_discrete_syms : discrete (syms Σ').
proof: Proof. intros (s1 & H1) (s2 & H2). destruct (HΣ1 s1 s2) as [ | C ]. + left; subst; f_equal; apply eq_bool_pirr. + right; contradict C; injection C; auto. Qed.
imports: List Arith Bool Lia Eqdep_dec Max Undecidability.Shared.Libs.DLW.Utils(utils_tac utils_list utils_nat finite) Undecidability.Shared.Libs.DLW.Vec(pos vec) Undecidability.FOL.TRAKHTENBROT(notations utils decidable fol_ops fo_sig fo_terms fo_logic fo_sat)