English
If every member s(n) is independent from s' with respect to μ, then the intersection over all n of s(n) is independent from s' with respect to μ.
Русский
Если каждый член \\(s(n)\\) независим относительно \\(s'\\) по μ, то пересечение всех \\(s(n)\\) независимо от \\(s'\\).
LaTeX
$$$\\Big( \\forall n, IndepSets(s(n), s'; \\mu) \\Big) \\Rightarrow IndepSets\\Big(\\bigcup_{n} s(n), s'; \\mu\\Big)$$$
Lean4
theorem iUnion {s : ι → Set (Set Ω)} {s' : Set (Set Ω)} (hyp : ∀ n, IndepSets (s n) s' μ) : IndepSets (⋃ n, s n) s' μ :=
Kernel.IndepSets.iUnion hyp