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arXiv · 0908.4342

Malnormal subgroups of lattices and the Pukanszky invariant in group factors

Guyan Robertson·Tim Steger
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Abstract

Let $G$ be a connected semisimple real algebraic group. Assume that $G(\bb R)$ has no compact factors and let $\Gamma$ be a torsion-free uniform lattice subgroup of $G(\bb R)$. Then $\Gamma$ contains a malnormal abelian subgroup $A$. This implies that the $\tto$ factor $\vn(\Gamma)$ contains a masa $\fk A$ with Puk\'anszky invariant $\{\infty\}$.

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Guyan Robertson, Tim Steger. 2009-08-29. Malnormal subgroups of lattices and the Pukanszky invariant in group factors. https://arxiv.org/abs/0908.4342

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