Explicit polynomial bounds on Dehn functions of subgroups of hyperbolic groups

Autor: Kropholler, Robert, Isenrich, Claudio Llosa, Soroko, Ignat
Rok vydání: 2025
Předmět:
Druh dokumentu: Working Paper
Popis: In 1999 Brady constructed the first example of a non-hyperbolic finitely presented subgroup of a hyperbolic group by fibring a non-positively curved cube complex over the circle. We show that his example has Dehn function bounded above by $n^{96}$. This provides the first explicit polynomial upper bound on the Dehn function of a finitely presented non-hyperbolic subgroup of a hyperbolic group. We also determine the precise hyperbolicity constant for the $1$-skeleton of the universal cover of the cube complex in Brady's construction with respect to the $4$-point condition for hyperbolicity.
Comment: 21 pages, 19 figures
Databáze: arXiv