This article is about polyhedra in algebraic topology. For polyhedra in convex geometry, see the article polytope.
topology (point-set topology, point-free topology)
see also differential topology, algebraic topology, functional analysis and topological homotopy theory
Basic concepts
fiber space, space attachment
Extra stuff, structure, properties
Kolmogorov space, Hausdorff space, regular space, normal space
sequentially compact, countably compact, locally compact, sigma-compact, paracompact, countably paracompact, strongly compact
Examples
Basic statements
closed subspaces of compact Hausdorff spaces are equivalently compact subspaces
open subspaces of compact Hausdorff spaces are locally compact
compact spaces equivalently have converging subnet of every net
continuous metric space valued function on compact metric space is uniformly continuous
paracompact Hausdorff spaces equivalently admit subordinate partitions of unity
injective proper maps to locally compact spaces are equivalently the closed embeddings
locally compact and second-countable spaces are sigma-compact
Theorems
Analysis Theorems
A topological space is a polyhedron if it is homeomorphic to the geometric realization of a finite simplicial complex and hence has a triangulation.
The study of polyhedra has been one of the sources for methods and applications in algebraic topology, and it is often useful to go back to see the motivations and applications in the older sources. For instance, shape morphisms between polyhedral spaces are just homotopy classes of continuous maps so the Cech invariants of polyhedra coincide with their ordinary ‘standard’ invariants.
Among textbook accounts:
Last revised on October 27, 2021 at 13:42:46. See the history of this page for a list of all contributions to it.