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Timeline for Shortcutting quasigeodesics

Current License: CC BY-SA 4.0

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Oct 14, 2021 at 10:38 vote accept Ashot Minasyan
Oct 14, 2021 at 8:48 answer added Florian Lehner timeline score: 4
Oct 12, 2021 at 21:14 comment added Ashot Minasyan @FlorianLehner: you are right, thanks for your comments. If you decide to put them as an answer I would be happy to accept it.
Oct 12, 2021 at 15:26 comment added Florian Lehner @AshotMinasyan: If I'm not mistaken, then a path is a $(1,c)$-quasigeodesic if and only if its length exceeds the distance between its endpoints by at most $c$, i.e. we only need to check the whole path, not all sub-paths. This property is certainly preserved under replacing a subpath by a shorter (or equally long) one.
Oct 12, 2021 at 14:43 comment added Ashot Minasyan @FlorianLehner: thanks, that's a great counter-example for both questions! I have thought about the same path, but treated it as a $(1,2k)$-quasigeodesic, instead of changing the multiplicative constant! What if I require $\lambda=1$?
Oct 12, 2021 at 14:31 comment added Florian Lehner here is an easy counterexample in $\mathbb Z^2$: the path [$k$ steps up, $k$ steps right, $k$ steps down] is a $(3,0)$ quasi-geodesic, but replacing the first $2k$ steps by the geodesic [$(k-1)$ steps right, $k$ steps up, one step right] does not preserve this.
Oct 12, 2021 at 14:20 comment added markvs How about ${\mathbb Z}^2$? There are many geodesics with the same endpoints there.
Oct 12, 2021 at 14:08 history asked Ashot Minasyan CC BY-SA 4.0