fact: Definition OU (I: orduni) := exists (Delta: ctx) (sigma: fin -> exp X), Delta ⊩(n) sigma : Gamma₀ /\ sigma • s₀ ≡ sigma • t₀.
imports: List Lia Morphisms Undecidability.HOU(std.std calculus.calculus unification.higher_order_unification unification.systemunification)