Can smooth manifold have a corner
11319
Is $M=\{(x,|x|): x \in (-1, 1)\}$ not a differentiable manifold?
69798
Intersecting geodesics in a positive curvature manifold
28393
Smooth a Cylinder in one direction
110691
Proving that given any two points in a connected manifold, there exists a diffeomorphism taking one to the other
7945
Approximate $|x|$ with a smooth function
135126
Proving that the quotient manifold is orientable if and only if the group action is orientation-preserving
68234
Is $[0,1) \cup \{2\}$ a manifold with boundary? My issue is the $2$.
149593
Global sections of a tensor product of vector bundles on a smooth manifold
133465
Stokes and Gauss' Divergence theorem on a closed smooth surface in $\Bbb R^3$
64920
Boundary Question in $\mathbb{R}^{2}$ (Manifolds)
61255
Tangent bundle : is a manifold
44955
Can $\mathbb CP^n$ be the boundary of a compact manifold?
258
Existence of orthogonal coordinates on a Riemannian manifold
95221
Is the cuspidal cubic $\{y^2 = x^3\} \subset \Bbb R^2$ not smooth?
76937
Is there an elementary way to see that there is only one complex manifold structure on $R^2$?
143929
dimension of a connected Manifold
136592
Examples of manifolds that are not boundaries