Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Commensurating HNN-extensions: hierarchical hyperbolicity and
  biautomaticity   We construct a CAT(0) hierarchically hyperbolic group (HHG) acting
geometrically on the product of a hyperbolic plane and a locally-finite tree
which is not biautomatic. This gives the first example of an HHG which is not
biautomatic, the first example of a non-biautomatic CAT(0) group of flat-rank
2, and the first example of an HHG which is injective but not Helly. Our proofs
heavily utilise the space of geodesic currents for a hyperbolic surface.

31
The categories of this paper are: ao-sci
12
The categories of this paper are: nucl-th
1
The categories of this paper are: cs
24
The categories of this paper are: dg-ga
9
The categories of this paper are: nlin
16
The categories of this paper are: stat
33
The categories of this paper are: plasm-ph
36
The categories of this paper are: cmp-lg
8
The categories of this paper are: hep-ex
35
The categories of this paper are: mtrl-th
34
The categories of this paper are: chem-ph
30
The categories of this paper are: q-alg
14
The categories of this paper are: math-ph
15
The categories of this paper are: nucl-ex
25
The categories of this paper are: patt-sol
18
The categories of this paper are: econ