Zulip Chat Archive
Stream: Is there code for X?
Topic: pushforward of product topology is product topology
Kevin Buzzard (Aug 24 2024 at 23:28):
Do we have anything like
import Mathlib.Topology.Constructions
example {ι κ : Type*} (e : ι ≃ κ) (X : Type*) [TopologicalSpace X] :
TopologicalSpace.coinduced (fun f ↦ f ∘ e : (κ → X) → (ι → X)) Pi.topologicalSpace =
Pi.topologicalSpace := by
sorry
Mathematically I'm asking that the product topologies on and coincide given a bijection . The map (κ → X) → (ι → X)
can be beefed up to can equiv with Equiv.piCongrLeft'
if necessary. I tried doing this with some lattice manipulations but didn't get anywhere, and breaking it up into <= and >= didn't look like much fun either.
Yury G. Kudryashov (Aug 24 2024 at 23:58):
We have docs#Homeomorph.piCongrLeft
Kevin Buzzard (Aug 25 2024 at 07:42):
Perfect, thanks!
Last updated: May 02 2025 at 03:31 UTC