-| RLet : ∀ Γ Δ Σ₁ Σ₂ σ₁ σ₂ l, Rule ([Γ>Δ> Σ₂ |- [σ₂@@l]],,[Γ>Δ> Σ₁,,[σ₂@@l] |- [σ₁@@l] ]) [Γ>Δ> Σ₁,,Σ₂ |- [σ₁ @@l]]
+| RLet : ∀ Γ Δ Σ₁ Σ₂ σ₁ σ₂ l, Rule ([Γ>Δ> Σ₁ |- [σ₁]@l],,[Γ>Δ> [σ₁@@l],,Σ₂ |- [σ₂]@l ]) [Γ>Δ> Σ₁,,Σ₂ |- [σ₂ ]@l]
+| RWhere : ∀ Γ Δ Σ₁ Σ₂ Σ₃ σ₁ σ₂ l, Rule ([Γ>Δ> Σ₁,,([σ₁@@l],,Σ₃) |- [σ₂]@l ],,[Γ>Δ> Σ₂ |- [σ₁]@l]) [Γ>Δ> Σ₁,,(Σ₂,,Σ₃) |- [σ₂ ]@l]