# Dan Sălăjan

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bio website location age member for 11 months seen 13 hours ago profile views 518
postdoc in Leipzig, before in Lausanne.

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 Dec11 comment An example of a non-amenable exact group without free subgroups. I don't think the group above is known to be exact. Nov20 answered Uniform bounds on Kazhdan constants in groups Nov20 comment Uniform bounds on Kazhdan constants in groups It seems so, by Gelander and Zuk ams.org/mathscinet/search/… Nov15 comment Folner sets and balls Thanks so much for this beautiful post! Accidentally, I also analyzed this presentation (and I'm an old fan of the combinatorial hyperbolic plane). I need to think more about your intuition concerning arbitrarly generating sets. Nov15 comment Folner sets and balls In general a free semigroup won't help you that much, since you need both lower and upper bounds estimation on the sizes of balls... Nov15 comment Folner sets and balls It looks unlikely, nevertheless, I don't have a disproof. In fact, the shape of Folner sets in exponential growth groups is quite unclear to me, so I asked the most basic question I could come up with. I have no decent evidence for or against, but often enough the quantity $liminf c_{n+1}/c_n$, where $c_n$ is the size of the ball, is less than the growth... so it is not clear so far. Nov15 comment Folner sets and balls Thanks for the comment. A sequence of balls in my phrasing was meant to be a subsequence of the sequence of the balls, indeed. I hope it is clear. Nov15 revised Folner sets and balls edited body Nov15 asked Folner sets and balls Nov6 awarded Nice Answer Nov4 answered Is there an infinite group with exactly two conjugacy classes? Oct19 answered New trends in Applied Graph Theory Oct9 awarded Caucus Oct9 answered Rotation numbers for amenable group actions on the circle Oct1 comment Speed of random walks in groups You re welcome. Very interesting, I don´t know any reference or proof... I might think about it, maybe there is a simple reason for it. I let you know if I succeed. Dan Sep4 awarded Enthusiast Aug28 comment Expected edit distance @Carl: No, that typo escaped 6 edits :). Aug28 awarded Organizer Aug28 revised Expected edit distance Added the Computer Science tag, since the metric in question is mostly studied by computer scientists. Aug28 suggested suggested edit on Expected edit distance