New posts in algebraic-topology

Steenrod Algebra as automorphisms of additive group

algebraic-geometry algebraic-topology homotopy-theory formal-groups cohomology-operations

$\mathbb{R}\text{P}^{n-1}$ is not retract of $\mathbb{R}\text{P}^n$

algebraic-topology projective-space

Nonisomorphic vector bundles with diffeomorphic total spaces

algebraic-topology differential-topology vector-bundles

Second homotopy group of real Grassmannians $\textrm{Gr}(n,m)$, special case $n=m=2$ not clear.

general-topology algebraic-topology homotopy-theory exact-sequence grassmannian

A short exact sequence of groups and their classifying spaces

reference-request algebraic-topology topological-groups fibration exact-sequence

Explicit examples of (co)limit arguments in other fields

abstract-algebra algebraic-geometry algebraic-topology category-theory big-list

Covering space of a non-orientable surface

algebraic-topology covering-spaces

Product of simplicial complexes?

combinatorics algebraic-topology simplicial-stuff

Does the integral cohomology ring determine the ring structure with other coefficients?

algebraic-topology manifolds homology-cohomology

Intersection Pairing and Poincaré Duality

algebraic-topology homology-cohomology duality-theorems

Is this a different proof of the fundamental group being abelian?

general-topology algebraic-topology topological-groups fundamental-groups

Find the fundamental group of a topological space X obtained from S3 by removing a figure 8

general-topology algebraic-topology fundamental-groups

Why is the classification of topological spaces up to homeomorphism impossible or undesirable?

general-topology algebraic-topology

Are homotopic maps over a cofibration homotopic relative to the cofibration?

algebraic-topology

What are all topological spaces obtained by gluing the edges of a triangle?

algebraic-topology surfaces

Explanation for a line from a MathOverflow answer

algebraic-topology homotopy-theory equivariant-cohomology

Spin structures, frame bundles, and trivializations over the 2-skeleton

algebraic-topology vector-bundles fiber-bundles

Understanding Poincare Duality

algebraic-topology differential-topology geometric-topology duality-theorems

Can the Gauss-Bonnet theorem be proven from Stokes's theorem?

differential-geometry algebraic-topology stokes-theorem

Question from J. Milnor paper from 1968 about diffeomorphic manifolds

algebraic-geometry algebraic-topology differential-topology heisenberg-group