Stefan Friedl
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Registered User
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Apr 30 |
comment |
Rank gradients and HNN-extensions Thanks Yves for your comments. I like the example the example where $\operatorname{rank}(F^n)$ grows logarithmically. I was aware of the relationship to the groups $\Lambda_n$, in fact in a paper with Jason DeBlois and Stefano Vidussi we played such games to show that the rank gradient is non-zero if the HNN-extension is the fundamental group of a 3-manifold and where the HNN-extension does not correspond to a fiber bundle. We used a lot of heavy 3-manifold machinery (Agol, Wise et al) to show that the rank gradient is non-zero, and I was wondering whether all this is really necessary. |
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Apr 27 |
revised |
Rank gradients and HNN-extensions deleted 1 characters in body |
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Apr 26 |
asked | Rank gradients and HNN-extensions |
