New posts in algebraic-topology

The Join of Two Copies of $S^1$

Fundamental group of the Klein bottle, using action of a group?

deformation-retracts into a point / contractible : what is the difference?

Hairy Ball Theorem: homotopy from the identity to the antipodal map

Do we distinguish two singular simplices if they have different vertex orders?

Problem with definition of covering space

How do you prove that the dunce cap is not a surface?

What are examples of parallelizable complex projective varieties?

Rotman's Algebraic Topology Lemma 6.11

Covering spaces Hatcher question 6.

Braid groups and the fundamental group of the configuration space of $n$ points

Function doesn't have a lift in a space related to Topologist's sine curve

Knot with genus $1$ and trivial Alexander polynomial?

Relating the normal bundle and trivial bundles of $S^n$ to the tautological and trivial line bundles of $\mathbb{R}P^n$

Comparing notions of degree of vector bundle

$S^2=SO(3)/SO(2)$. Does this mean that $S^2 = SU(2)/U(1) $?

How to see that SL(2,C) is simply connected?

how to compute the Euler characters of a Grassmannian?

Why is Top a model category?

What is the class of topological spaces $X$ such that the functors $\times X:\mathbf{Top}\to\mathbf{Top}$ have right adjoints?