Skip to main content
21 events
when toggle format what by license comment
Sep 11, 2017 at 7:43 vote accept azureai
Sep 9, 2017 at 7:38 answer added Sam Nead timeline score: 2
Sep 9, 2017 at 5:27 history edited azureai CC BY-SA 3.0
added 23 characters in body
Sep 9, 2017 at 0:46 comment added azureai How about what I proposed in my second edit. Do the deleted object and $\mathbb{D}_n$ have the same mapping class group?
Sep 8, 2017 at 21:30 history edited azureai CC BY-SA 3.0
added 643 characters in body
Sep 8, 2017 at 20:42 history edited azureai
edited tags
Sep 8, 2017 at 18:38 history edited azureai CC BY-SA 3.0
added 168 characters in body
Sep 8, 2017 at 18:23 history edited azureai CC BY-SA 3.0
typo
Sep 8, 2017 at 8:14 comment added YCor $\pi_1(D_n)$ is not QI to $\tilde{D}_n$ because the former is a free group (so has 0, 2 or $\infty$ ends), while the second one is the hyperbolic space and hence has 1 end.
Sep 8, 2017 at 1:36 comment added Lee Mosher 2) is mis-copied from earlier in the question where it asks whether $\pi_1(\mathbb{D}_n)$ is quasi-isometric to $\widetilde{\mathbb{D}}_n$. However, that's not really a sensible question either. It is certainly sensible to ask whether the orbit map $\pi_1(\mathbb{D}_n) \to \widetilde{\mathbb{D}}_n$ of the action is a quasi-isometry, but the answer is "no" because the action is not cobounded.
Sep 7, 2017 at 23:25 history edited azureai CC BY-SA 3.0
added 12 characters in body
Sep 7, 2017 at 23:19 history edited azureai CC BY-SA 3.0
added 12 characters in body
Sep 7, 2017 at 23:13 history edited azureai CC BY-SA 3.0
added 12 characters in body
Sep 7, 2017 at 23:08 history edited azureai CC BY-SA 3.0
formatting
Sep 7, 2017 at 23:02 history edited azureai CC BY-SA 3.0
formatting
Sep 7, 2017 at 22:56 history edited azureai CC BY-SA 3.0
typos
Sep 7, 2017 at 22:22 comment added YCor $\pi_1(\mathbb{D}_n)$ is free on $n$ generators, so has infinitely many ends for $n\ge 2$, while $\mathbb{D}_n$ has finitely many ends ($n+1$). So they are not quasi-isometric. For $n=1$, $\mathbb{D}_1$ (punctured disk) can't be endowed with a hyperbolic metric for which both ends are cusps. Anyway, for any complete hyperbolic metric, it will have exponential growth, while the fundamental group $\mathbf{Z}$ has linear growth, so again they are not QI for $n=1$ as well (a similar argument works for $n=0$).
Sep 7, 2017 at 22:17 history edited azureai CC BY-SA 3.0
added 152 characters in body; edited tags
Sep 7, 2017 at 22:16 history edited YCor
edited tags
Sep 7, 2017 at 22:00 review First posts
Sep 7, 2017 at 22:02
Sep 7, 2017 at 21:56 history asked azureai CC BY-SA 3.0