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We show that PSL(2,Z[1/p]) admits a combing with bounded asynchronous width, and use this combing to show that PSL(2,Z[1/p]) has an exponential Dehn function. As a corollary, PSL(2,Z[1/p]) has solvable word problem and is not an automatic group.
In this paper, we compute an upper bound for the Dehn function of a finitely presented metabelian group. In addition, we prove that the same upper bound works for the relative Dehn function of a finitely generated metabelian group. We also show that
We construct a finitely presented group with quadratic Dehn function and undecidable conjugacy problem. This solves E. Rips problem formulated in 1992. v2: misprints corrected. v3: lemmas 4.7, 4.10 corrected, more misprints fixed.
We show that an element w of a free group F on n generators defines a surjective word map of PSL(2,C)^n onto PSL(2,C) unless w belongs to the second derived subgroup of F. We also describe certain words maps that are surjective on SL(2,C) x SL(2,C). Here C is the field of complex numbers.
We show that the Dehn function of the handlebody group is exponential in any genus $ggeq 3$. On the other hand, we show that the handlebody group of genus $2$ is cubical, biautomatic, and therefore has a quadratic Dehn function.
In this paper we prove that for Gromov-Witten theory of $P^1$ orbifolds of ADE type the genus-2 G-function introduced by B. Dubrovin, S. Liu, and Y. Zhang vanishes. Together with our results in [LW], this completely solves the main conjecture in thei