fact: Definition Σ2_is_fun l s := ∀∀∀∀∀ 2 ∈ (5+l) ⤑ 1 ∈ (5+l) ⤑ 4 ∈ (5+s) ⤑ 3 ∈ (5+s) ⤑ Σ2_is_opair 4 2 0 ⤑ Σ2_is_opair 3 1 0 ⤑ 2 ≈ 1.
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)