Theorems · Theorem · general topology

OpenPartialHomeomorph.isOpen_image_source_inter

∀ {X : Type u_1} {Y : Type u_3} [inst : TopologicalSpace X] [inst_1 : TopologicalSpace Y]
  (e : OpenPartialHomeomorph X Y) {s : Set X}, IsOpen s → IsOpen (↑e '' (e.source ∩ s))

The image of the restriction of an open set to the source is open.

Defined in

Mathlib.Topology.OpenPartialHomeomorph.Basic

Cited by

1 results in Mathlib

Foundations

Depth 80 from the axioms · uses propext, Classical.choice, Quot.sound

Assumes

TopologicalSpaceTopologicalSpace