proposition: Lemma decomp_irrefl s t E: decomp s t = Some E -> forall u v, (u,v) ∈ E -> u <> v.
proof: Proof. decomp_ind; cbn. all: intuition idtac; simplify in *; try congruence. subst; destruct H4; eauto. Qed.
imports: List Lia Arith Init.Wf Morphisms Program.Program Undecidability.HOU(concon.conservativity calculus.calculus) Undecidability.HOU.unification(systemunification nth_order_unification)