English
If every pair of elements a ∈ S and b ∈ T has disjoint supports, then the closures of S and T are disjoint.
Русский
Если каждый элемент a из S и b из T имеют взаимноdisjoint поддержки, то замыкания S и T дисjoint.
LaTeX
$$$\\forall a \\in \\overline{S}, \\forall b \\in \\overline{T}, \\operatorname{Disjoint}(a.\\operatorname{support}, b.\\operatorname{support}).$$$
Lean4
theorem disjoint_support_closure_of_disjoint_support {S T : Set (Perm α)}
(h : ∀ a ∈ S, ∀ b ∈ T, _root_.Disjoint a.support b.support) :
∀ a ∈ closure S, ∀ b ∈ closure T, _root_.Disjoint a.support b.support :=
by
intro a ha b hb
have key1 := support_closure_subset_union S a ha
have key2 := support_closure_subset_union T b hb
have key := Set.disjoint_of_subset key1 key2
simp_rw [Set.disjoint_iUnion_left, Set.disjoint_iUnion_right, Finset.disjoint_coe] at key
exact key h