fact: Definition mb_has_pairs (l : X) := forall x y, x ∈ l -> y ∈ l -> exists p, p ≋ ⦃x,y⦄ .
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)