English
Upper polar distributes over union: upperPolar r (s1 ∪ s2) = upperPolar r s1 ∩ upperPolar r s2.
Русский
Upper polar распределяется по объединению: upperPolar r (s1 ∪ s2) = upperPolar r s1 ∩ upperPolar r s2.
LaTeX
$$$\upperPolar r (s_1 \cup s_2) = \upperPolar r s_1 \cap \upperPolar r s_2$$$
Lean4
@[simp]
theorem upperPolar_union (s₁ s₂ : Set α) : upperPolar r (s₁ ∪ s₂) = upperPolar r s₁ ∩ upperPolar r s₂ :=
ext fun _ => forall₂_or_left