Geodesic
Commensurations and subgroups of finite index of Thompson’s group F
Burillo, José1 ; Cleary, Sean2 ; Röver, Claas E3
1 Departament de Matemàtica Aplicada IV, Universitat Politècnica de Catalunya, Escola Politècnica Superior de Castelldefels, Avda. Del Canal Olímpic 15, 08860 Castelldefels (Barcelona), Spain
2 Department of Mathematics R8133, The City College of New York, Convent Ave & 138th, New York, NY 10031, USA
3 Department of Mathematics, University of Ireland, Galway, University Road, Galway, Ireland
Geometry & topology, Tome 12 (2008) no. 3, pp. 1701-1709.

Voir la notice de l'article provenant de la source Mathematical Sciences Publishers

We determine the abstract commensurator Com(F) of Thompson’s group F and describe it in terms of piecewise linear homeomorphisms of the real line. We show Com(F) is not finitely generated and determine which subgroups of finite index in F are isomorphic to F. We also show that the natural map from the commensurator group to the quasi-isometry group of F is injective.

DOI : 10.2140/gt.2008.12.1701
Keywords: Thompson group, commensurator

Burillo, José 1 ; Cleary, Sean 2 ; Röver, Claas E 3

1 Departament de Matemàtica Aplicada IV, Universitat Politècnica de Catalunya, Escola Politècnica Superior de Castelldefels, Avda. Del Canal Olímpic 15, 08860 Castelldefels (Barcelona), Spain
2 Department of Mathematics R8133, The City College of New York, Convent Ave & 138th, New York, NY 10031, USA
3 Department of Mathematics, University of Ireland, Galway, University Road, Galway, Ireland 
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Burillo, José; Cleary, Sean; Röver, Claas E. Commensurations and subgroups of finite index of Thompson’s group F. Geometry & topology, Tome 12 (2008) no. 3, pp. 1701-1709. doi : 10.2140/gt.2008.12.1701. http://geodesic.mathdoc.fr/articles/10.2140/gt.2008.12.1701/

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