85173 driver artpubuab oai:ddd.uab.cat:85173 articleid 02141493v56n1p255 doi 10.5565/PUBLMAT_56112_09 eng Kar, Aditi Some non-amenable groups We generalise a result of R. Thomas to establish the non-vanishing of the first L2 Betti number for a class of nitely generated groups. Article de fons Finitely generated groups Orbifolds Cohomology Euler characteristic info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion Niblo, Graham A. Vol. 56, Núm. 1 ( 2012), p. 255-259 Publicacions matemàtiques 0214-1493 5 275815 http://ddd.uab.cat/uab/pubmat/02141493v56n1/pubmat_a2012v56n1p255.pdf 0255 259 1 56 02141493v56n1 2012 ARTPUB UAB PUBMAT Tots els drets reservats http://www.europeana.eu/rights/rr-f/