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arXiv · 1309.0492

Commensurators of solvable S-arithmetic groups

Daniel Studenmund
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Abstract

We show that the abstract commensurator of an S-arithmetic subgroup of a solvable algebraic group over Q is isomorphic to the Q-points of an algebraic group, and compare this with examples of nonlinear abstract commensurators of S-arithmetic groups in positive characteristic. In particular, we include a description of the abstract commensurator of the lamplighter group.

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Daniel Studenmund. 2013-09-02. Commensurators of solvable S-arithmetic groups. https://doi.org/10.2140/pjm.2016.283.201

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