Prove that there is not a retraction of the Möbius band to its boundary
88616
Retraction of the Möbius strip to its boundary
151735
$\mathbb{R}^3 \setminus A$ deformation retracts onto $S^1 \vee S^2$
69871
How to prove Poincaré-like inequality for the integral over the boundary?
88317
Let gh be a chord of a circle ω which is not a diameter, and let A be a fixed point on gh
25874
Showing that a certain map is not flat by explicit counterexample
118049
Show that $\mathbb{R}^{\mathbb{R}} = U_{e} \oplus U_{o}$
63731
Can we characterize the Möbius transformations that maps the unit disk into itself?
36485
$H_n(X,A) \not \approx \tilde{H}_n(X/A)$
119317
Proving the series of partial sums of $\sin (in)$ is bounded?
58000
How can one show that a möbius transformation maps the unit circle to some axis?
27775
Proving a function is not a contraction
33628
Prove that $\sin(\sqrt x)$ not periodic
41997
Can the boundary of a set be ignored, when integrating over it.
67383
Prove that $G'$ is not planar.
92802
Proof of Borsuk-Ulam Theorem .
47056
Show that the boundary of a set equals the boundary of its complement
158582
Prove that $\{\frac{\phi (n)}{n}\}_{n \in \Bbb N}$ is dense in $[0,1]$