An atlas pulled back by a homeomorphism
DefinitionSP4PullbackChartsFor topological spaces M and N and a chart model H, a homeomorphism e : N ≃ₜ M transports the given H-charted-space structure on M to N by composition of its charts with e. The construction is universe-polymorphic.
-- Derived from frozen local sources; exact source/hash provenance in items.json.
import Mathlib
set_option autoImplicit false
namespace SP4Mission
open _root_.Homeomorph
open Set ChartedSpace
open scoped Manifold Topology
variable {H : Type*} [TopologicalSpace H] {M : Type*} [TopologicalSpace M]
[ChartedSpace H M] {N : Type*} [TopologicalSpace N]
namespace Homeomorph
@[instance_reducible]
def _root_.Homeomorph.sp4MissionPullbackChartedSpace (e : N ≃ₜ M) : ChartedSpace H N where
atlas := (e.transOpenPartialHomeomorph ·) '' atlas H M
chartAt x := e.transOpenPartialHomeomorph (chartAt H (e x))
mem_chart_source x := mem_chart_source H (e x)
chart_mem_atlas x := ⟨_, chart_mem_atlas _ (e x), rfl⟩
end Homeomorph
end SP4Mission
Read-back
What the Lean code literally says, in plain math · Codex; the exact underlying model identifier is not exposed in this session.
For every topological model space , every topological space with a specified charted-space structure modeled on , every topological space , and every homeomorphism , the construction defines a charted-space structure on modeled on the same . Its atlas consists exactly of the charts obtained by first applying and then an atlas chart of : such a chart has source , target , forward map , and inverse map . The preferred chart at each is obtained from the preferred chart of at by this same composition. The topology on is its given topology, and no earlier chart structure on , differentiability, manifold compatibility, dimension, separation, or nonemptiness hypothesis is required; empty spaces are included whenever the stated homeomorphism exists.
Confirmed by the mission captain (proposal self-audit).