eng Anglès Thompson’s group is the orientation-preserving automorphism group of a cellular complex Fossas, A. Nguyen, M. info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion 2012 Mapping class groups Ip complex Infinite type surfaces Group actions Thompson's groups Publicacions matemàtiques http://ddd.uab.cat/record/91307 10.5565/PUBLMAT_56212_03 02141493v56n2p305 oai:ddd.uab.cat:91307 Tots els drets reservats http://www.europeana.eu/rights/rr-f/ We consider a planar surface ∑ of in nite type which has Thompson's group T as asymptotic mapping class group. We construct the asymptotic pants complex C of ∑ and prove that the group T acts transitively by automorphisms on it. Finally, we establish that the automorphism group of the complex C is an extension of the Thompson group T by Z=2Z.