homotopy theory, (∞,1)-category theory, homotopy type theory
flavors: stable, equivariant, rational, p-adic, proper, geometric, cohesive, directed…
models: topological, simplicial, localic, …
see also algebraic topology
Introductions
Definitions
Paths and cylinders
Homotopy groups
Basic facts
Theorems
A homology sphere is a topological space which need not be homeomorphic to an n-sphere, but which has the same ordinary homology as an -sphere.
Every homology sphere is a rational homology sphere.
Every homotopy sphere is a homology sphere.
Every simply connected homology sphere is a homotopy sphere.
There are simply connected homology--spheres not homeomorphic to the -sphere iff .
Last revised on March 21, 2024 at 12:11:37. See the history of this page for a list of all contributions to it.