New posts in algebraic-topology

Identifying boundary of solid torus with itself by swapping coordinates

Show that if B is simply-connected, then p is a homeomorphism.

$K(\mathbb R P^n)$ from $K(\mathbb C P^k)$

Visualize Fourth Homotopy Group of $S^2$

Is the torus the union of two connected, simply-connected open sets?

Cell decomposition for $\mathbb{C}P^n$ that has $\mathbb{R}P^n$ as a subcomplex?

Possible mistake in Bloch Book: $\Bbb S^2\#\Bbb S^2\#\dots\cong\Bbb S^2$!

What are the isomorphism classes of $\pi_1(\mathbb{R}^2\setminus C)$ where $C$ ranges over all countable subsets of $\mathbb{R}^2$?

Top deRham cohomology group of a compact orientable manifold is 1-dimensional

Question on showing a bijection between $\pi_1(X,x_0)$ and $[S^1, X]$ when X is path connected.

Relation between Stiefel-Whitney class and Chern class

Natural examples of deformation retracts that are not strong deformation retracts

Can contractible subspace be ignored/collapsed when computing $\pi_n$ or $H_n$?

Is the Euler characteristic of $\mathbb{R}^n$ $1$ or $(-1)^n$?

contractible and simply connected

Does homotopy equivalence of pairs distinguish knots?

If the connected sum of a manifold $M$ with itself gives back $M$, does it imply $M$ is a sphere?

The "Wu formula" and Steenrod algebras

Contractible vs. Deformation retract to a point. [duplicate]

Understanding the definition of a cofibration