Timeline for Examples of hyperbolic groups with non-hyperbolic subgroups
Current License: CC BY-SA 4.0
3 events
| when toggle format | what | by | license | comment | |
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| Jul 13, 2022 at 9:53 | comment | added | HJRW | Very nice! ${}{}$ | |
| Jul 12, 2022 at 20:05 | comment | added | Matt Zaremsky | I think you can also do as @HJRW suggested and build a different map from Brady's group to $\mathbb{Z}$ whose kernel is f.g. but not f.p. Brady builds his Morse function starting with a map from $\Theta^3$ to $S^1$ that wraps the edges around so as to ensure every ascending and descending link is a 2-sphere. If you instead "kill" one of the pairs of ascending directions and one of the pairs of descending directions, making them "flat", I believe now every ascending and descending link (of either a vertex or a flat edge) is a circle. (And then the kernel thing follows.) | |
| Jul 12, 2022 at 17:48 | history | answered | Moishe Kohan | CC BY-SA 4.0 |