fact: Variable (P : fo_term -> Type) (HP0 : forall x, P (in_var x)) (IHP : forall s v, (forall p, P (vec_pos v p)) -> P (@in_fot s v)).
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)