+Definition RLet : ∀ Γ Δ Σ₁ Σ₂ σ₁ σ₂ l,
+ ND Rule ([Γ>Δ> Σ₁ |- [σ₁]@l],,[Γ>Δ> [σ₁@@l],,Σ₂ |- [σ₂]@l ]) [Γ>Δ> Σ₁,,Σ₂ |- [σ₂ ]@l].
+ intros.
+ eapply nd_comp; [ idtac | eapply nd_rule; eapply RArrange; eapply ACanL ].
+ eapply nd_comp; [ idtac | eapply nd_rule; eapply RCut ].
+ apply nd_prod.
+ apply nd_id.
+ eapply nd_rule; eapply RArrange; eapply AuCanL.
+ Defined.
+
+Definition RWhere : ∀ Γ Δ Σ₁ Σ₂ Σ₃ σ₁ σ₂ l,
+ ND Rule ([Γ>Δ> Σ₁,,([σ₁@@l],,Σ₃) |- [σ₂]@l ],,[Γ>Δ> Σ₂ |- [σ₁]@l]) [Γ>Δ> Σ₁,,(Σ₂,,Σ₃) |- [σ₂ ]@l].
+ intros.
+ eapply nd_comp; [ apply nd_exch | idtac ].
+ eapply nd_rule; eapply RCut.
+ Defined.
+