English
(a ⊓ b)ᶜᶜ = aᶜᶜ ⊓ bᶜᶜ.
Русский
(a ⊓ b)ᶜᶜ = aᶜᶜ ⊓ bᶜᶜ.
LaTeX
$$$(a \land b)^{\complement\complement} = a^{\complement\complement} \land b^{\complement\complement}$$$
Lean4
theorem compl_compl_inf_distrib (a b : α) : (a ⊓ b)ᶜᶜ = aᶜᶜ ⊓ bᶜᶜ :=
by
refine ((compl_anti compl_sup_compl_le).trans (compl_sup_distrib _ _).le).antisymm ?_
rw [le_compl_iff_disjoint_right, disjoint_assoc, disjoint_compl_compl_left_iff, disjoint_left_comm,
disjoint_compl_compl_left_iff, ← disjoint_assoc, inf_comm]
exact disjoint_compl_right