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arXiv · 0708.2494

A formula for the normal subgroup growth of Baumslag-Solitar groups

J. O. Button
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Abstract

We give an exact formula for the number of normal subgroups of each finite index in the Baumslag-Solitar group BS(p,q) when p and q are coprime. Unlike the formula for all finite index subgroups, this one distinguishes different Baumslag-Solitar groups and is not multiplicative. This allows us to give an example of a finitely generated profinite group which is not virtually pronilpotent but whose zeta function has an Euler product.

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J. O. Button. 2007-08-18. A formula for the normal subgroup growth of Baumslag-Solitar groups. https://arxiv.org/abs/0708.2494

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