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636104
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visits member for 3 years, 9 months
seen 8 hours ago

Sep
2
asked Surface of genus $g$ does not retract to circle (Hatcher exercise)
Sep
1
accepted Typo in Hatcher? $\mathbb{R}^n - \{x \} \cong S^{n-1} \times \mathbb{R}$?
Sep
1
asked Typo in Hatcher? $\mathbb{R}^n - \{x \} \cong S^{n-1} \times \mathbb{R}$?
Sep
1
accepted Entangled circle in a solid torus (follow up)
Sep
1
comment Entangled circle in a solid torus (follow up)
OK, that is only after embedding $A$ in $X$ via $i$!
Sep
1
comment Entangled circle in a solid torus (follow up)
I thought $\pi_1(A, x_0) = 0$ because $A$ is contractible. So there is a contradiction: it's homeomorphic to a circle and homotopy equivalent to a point. Both yielding the same fundamental groups?
Aug
31
revised Entangled circle in a solid torus (follow up)
added 182 characters in body
Aug
31
revised Entangled circle in a solid torus (follow up)
added 164 characters in body
Aug
31
accepted Why is this entangled circle not a retract of the solid torus?
Aug
31
accepted Locally star-shaped space and piecewise linear path
Aug
31
comment Locally star-shaped space and piecewise linear path
Could I not choose a smaller $t_1$ in that case?
Aug
31
asked Locally star-shaped space and piecewise linear path
Aug
29
answered Inclusion of a neighbourhood is nullhomotopic
Aug
26
comment Inclusion of a neighbourhood is nullhomotopic
ooh, I see, thank you!
Aug
26
comment Proof that inclusion in disconnected space cannot be null-homotopic
Nice, thank you!
Aug
26
accepted Proof that inclusion in disconnected space cannot be null-homotopic
Aug
26
asked Proof that inclusion in disconnected space cannot be null-homotopic
Aug
26
asked Inclusion of a neighbourhood is nullhomotopic
Aug
25
accepted Meaning of $( \alpha_i = ((0,\dots, a_n, \dots, 0)) $ converges in $\mathbb{R}^\infty$
Aug
25
comment Cellular homology of projective space $\mathbb{R}P^n$
Oooh! So half of it is glued around one direction and the second half of it is glued around the opposite direction so that it becomes the $0$ map?