New posts in Manifolds

"A manifold with boundary has dimension at least 1" if it has a dimension and if it has nonempty boundary?

Does a topological space always admit a $\mathbb{Z}_2$-action?

Dual frame in Riemannian metrics.

Classification of surfaces

What does it mean for a vector field to be "along" $\partial M$? I think "along" is a generalization of "on".

Every connected orientable smooth manifold has exactly two orientations, Lee Proposition 15.9

Is $[0,1) \cup \{2\}$ a manifold with boundary? My issue is the $2$.

Manifold acted on by every finite group

Homology group of $X=\operatorname{SL}(2,\mathbb{R})/\operatorname{SL}(2,\mathbb{Z})$

Can the torus and the Klein bottle be thought as $\mathbb{R}^2/G$ with $G$ a finite group acting freely