fact: Fixpoint fot_word_var w i : fo_term (fun _ : X => 1) := match w with | nil => in_var i | s::w => in_fot s (fot_word_var w i##ø) end.
imports: List Arith Bool 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 fol_ops fo_sig fo_terms fo_logic fo_sat Sig_no_syms)