Diff$(S^1)$ is deformation retracts to $O(2)$
93471
Space of homeomorphisms Homeo$(S^1)$ of $S^1$ deformation retracts onto $O(2)$
83874
Prove that Hopf maps on $S^3, S^2$ and $\mathbb{C} \mathbb{P}^1$ are smooth submersions
117131
Canonical Isomorphism Between $\mathbf{V}$ and $(\mathbf{V}^*)^*$
132063
locally on $S$ one of the coordinates is a $C^∞$ function of the other coordinate. Show that $S$ is a submanifold of $R^2$
83273
Show that $o(gHg^{-1})=o(H)$
119794
Action of a 1-form on vector : changing of coordinates - tensor calculus
29453
An epimorphism from $S_{4}$ to $S_{3}$ having the kernel isomorphic to Klein four-group
65971
Double dual mappings
33868
A transformation between two free group actions.
72642
Continuous bijection from $(a,b) \to S^1$?
24828
surjective immersion $\mathbb{R}^2 \to \mathbb{R}^2$ which is not a diffeomorphism
127491
Isometric isomorphism between $R^2$ and $R$
11319
Is $M=\{(x,|x|): x \in (-1, 1)\}$ not a differentiable manifold?
30178
Homeomorphism $(\mathbb{CP}^1)^m/S_m \overset{\sim}{\to} \mathbb{CP}^m$?
157296
Homeomorphism between the Unit Disc and Complex Plane
54484
Natural examples of deformation retracts that are not strong deformation retracts
88616
Retraction of the Möbius strip to its boundary