English
If each member of a family S of subsets is stable under specialization, then their intersection is stable under specialization.
Русский
Если каждый элемент семейства S подмножеств устойчив по специализации, то их пересечение устойчиво по специализации.
LaTeX
$$$\Big(\forall s\in S, StableUnderSpecialization(s)\Big) \Rightarrow StableUnderSpecialization(\bigcap_{s\in S} s)$$$
Lean4
theorem stableUnderSpecialization_sInter (S : Set (Set X)) (H : ∀ s ∈ S, StableUnderSpecialization s) :
StableUnderSpecialization (⋂₀ S) :=
isLowerSet_sInter H