A normal subgroup theorem for commensurators of lattices

Darren Creutz*, Yehuda Shalom

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

5 Scopus citations


We establish a general normal subgroup theorem for commensurators of lattices in locally compact groups. While the statement is completely elementary, its proof, which rests on the original strategy of Margulis in the case of higher rank lattices, relies heavily on analytic tools pertaining to amenability and Kazhdan's property (T). It is a counterpart to the normal subgroup theorem for irreducible lattices of Bader and the second named author, and may also be used to sharpen that result when one of the ambient factors is totally disconnected.

Original languageEnglish
Pages (from-to)789-810
Number of pages22
JournalGroups, Geometry, and Dynamics
Issue number3
StatePublished - 2014


FundersFunder number
National Stroke Foundation
Directorate for Mathematical and Physical Sciences1007227


    • Commensurator
    • Contractive action
    • Factor theorem
    • Lattice
    • Normal subgroup theorem


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