International Journal of Mathematics and Mathematical Sciences
Volume 1 (1978), Issue 4, Pages 529-532
doi:10.1155/S0161171278000526
  
     
          
          On nonamenable groups
          
            Su-Shing Chen
          
          School of Mathematics, Georgia Institute of Technology, Atlanta 30332, Georgia, USA
          
          Abstract
A sufficient condition is given for a countable discrete group G to contain a free subgroup of two generators.