Abstract
We show that the abstract commensurator of is composed of four building blocks: two isomorphism types of simple groups, the multiplicative group of the positive rationals and a cyclic group of order two. The main result establishes the simplicity of a certain group of piecewise linear homeomorphisms of the real line.
Citation
José Burillo. Sean Cleary. Claas E Röver. "Addendum to “Commensurations and subgroups of finite index of Thompson's group $F$”." Geom. Topol. 17 (2) 1199 - 1203, 2013. https://doi.org/10.2140/gt.2013.17.1199
Information