English
Filter cocompact is the infimum of principal filters of complements to compact sets: ⨅ s IsCompact s, 𝓟 sᶜ.
Русский
Фильтр cocompact есть инфимум принципиев над дополнениями компактов: ⨅ s IsCompact s, 𝓟 sᶜ.
LaTeX
$$def cocompact : Filter X := ⨅ (s : Set X) (_ : IsCompact s), 𝓟 sᶜ$$
Lean4
/-- `Filter.cocompact` is the filter generated by complements to compact sets. -/
def cocompact : Filter X :=
⨅ (s : Set X) (_ : IsCompact s), 𝓟 sᶜ