Topological 3-manifolds
ClassTopological 3-manifold#✓fully proved
Let \(M\) be a topological space equipped with an atlas of charts, each a homeomorphism from an open subset of \(M\) onto an open subset of \(\mathbb{R}^3\), whose domains cover \(M\). Then \(M\) is a topological 3-manifold if it is Hausdorff and second-countable.
class IsThreeManifold (M : Type*) [TopologicalSpace M]
[ChartedSpace (EuclideanSpace ℝ (Fin 3)) M] : Prop
extends T2Space M, SecondCountableTopology M
ClassTopological 3-manifold with boundary#✓fully proved
A topological 3-manifold with boundary: a Hausdorff, second-countable topological space
locally homeomorphic to the Euclidean half-space EuclideanHalfSpace 2.
class IsThreeManifoldWithBoundary (M : Type*) [TopologicalSpace M]
[ChartedSpace (EuclideanHalfSpace 2) M] : Prop
extends T2Space M, SecondCountableTopology M
TheoremCharacterization of topological 3-manifolds#✓fully proved
Let \(M\) be a topological space equipped with an atlas of charts modelled on \(\mathbb{R}^3\), so that \(M\) is locally homeomorphic to \(\mathbb{R}^3\). Then \(M\) is a topological 3-manifold if and only if \(M\) is Hausdorff and second-countable.
theorem isThreeManifold_iff [ChartedSpace (EuclideanSpace ℝ (Fin 3)) M] :
IsThreeManifold M ↔ T2Space M ∧ SecondCountableTopology M
class IsThreeManifold (M : Type*) [TopologicalSpace M]
[ChartedSpace (EuclideanSpace ℝ (Fin 3)) M] : Prop
extends T2Space M, SecondCountableTopology M
MathlibExt/Topology/ThreeManifold.lean:38
Uses 1
TheoremTopological 3-manifolds are locally compact#✓fully proved
Every topological 3-manifold \(M\) is locally compact, since \(\mathbb{R}^3\) is.
theorem IsThreeManifold.locallyCompactSpace [ChartedSpace (EuclideanSpace ℝ (Fin 3)) M]
[IsThreeManifold M] : LocallyCompactSpace M
class IsThreeManifold (M : Type*) [TopologicalSpace M]
[ChartedSpace (EuclideanSpace ℝ (Fin 3)) M] : Prop
extends T2Space M, SecondCountableTopology M
MathlibExt/Topology/ThreeManifold.lean:38
Uses 1
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