α : Type u_1
inst✝ : CoheytingAlgebra α
a b : α
⊢ ∂ b ≤ ∂ (b ⊔ a) ⊔ ∂ (b ⊓ a)
α : Type u_1
inst✝ : CoheytingAlgebra α
a b : α
⊢ ∂ b ≤ ∂ (a ⊔ b) ⊔ ∂ (a ⊓ b)
rw [@sup_comm _ _ a, inf_comm]
no goals
α : Type u_1
inst✝ : CoheytingAlgebra α
a b : α
⊢ ∂ b ≤ ∂ (b ⊔ a) ⊔ ∂ (b ⊓ a)
exact boundary_le_boundary_sup_sup_boundary_inf_left