proposition: Fact fo_term_syms_fix_1 s v : fo_term_syms (@in_fot s v) = s::flat_map fo_term_syms (vec_list v).
proof: Proof. simpl; rewrite vec_list_vec_map, <- flat_map_concat_map; auto. Qed.
imports: List Arith Lia Eqdep_dec 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)