Section IMSELL.
Variable bang : Type.
Notation "£ A" := (@imsell_var _ _ A) (at level 1).
Notation "‼ l" := (@imsell_lban nat bang l).
Fact imsell_lban_perm Σ Γ : Σ ~p Γ -> ‼Σ ~p ‼Γ.
Fact S_imsell_cntr Γ Δ B : Forall (fun '(u,_) => U u) Γ -> ‼Γ++‼Γ++Δ ⊢ B -> ‼Γ++Δ ⊢ B.

Theorem S_imsell_weak_cntr Σ Γ u A B : (u,A) ∊ Σ -> U u -> ‼Σ++Γ ⊢ B <-> ![u]A::‼Σ++Γ ⊢ B.