Zulip Chat Archive

Stream: mathlib4

Topic: Intersecting all sets in a filter


Kevin Buzzard (Jul 22 2024 at 10:37):

The notation for Set.sInter won't eat a filter directly:

import Mathlib.Order.Filter.Basic

open Filter
example (A : Set 𝓧) : ⋂₀ (𝓟 A) = A := sorry -- doesn't compile
example (A : Set 𝓧) : ⋂₀ (𝓟 A).sets = A := sorry -- works fine

Would it be desirable/possible to extend this notation so that it applied to filters and returned a set?

Yaël Dillies (Jul 22 2024 at 10:39):

docs#Filter.ker


Last updated: May 02 2025 at 03:31 UTC