homotopy theory, (β,1)-category theory, homotopy type theory
flavors: stable, equivariant, rational, p-adic, proper, geometric, cohesive, directedβ¦
models: topological, simplicial, localic, β¦
see also algebraic topology
Introductions
Definitions
Paths and cylinders
Homotopy groups
Basic facts
Theorems
A rational homology sphere is a topological space which need not be homeomorphic to an n-sphere, but which has the same rational homology as an -sphere.
Every homology sphere is a rational homology sphere.
The Wu manifold is a simply connected rational homology -sphere (with non-trivial homology groups , and ), but isnβt a homotopy -sphere.
Last revised on May 31, 2024 at 15:04:15. See the history of this page for a list of all contributions to it.