Powers of sets in free groups
    
    
  
  
  
      
      
      
        
Sbornik. Mathematics, Tome 202 (2011) no. 11, pp. 1661-1666
    
  
  
  
  
  
    
      
      
        
      
      
      
    Voir la notice de l'article provenant de la source Math-Net.Ru
            
              			We prove that $|A^n|\geqslant c_n\cdot|A|^{[(n+1)/2]}$ for any finite subset $A$ of a free group if $A$ contains at least two noncommuting elements, where the $c_n>0$ are constants not depending on $A$. Simple examples
show that the order of these estimates is best possible for each $n>0$.
Bibliography: 5 titles.
			
            
            
            
          
        
      
                  
                    
                    
                    
                        
Keywords: 
free group, relations in a free group, subsets of a free group.
                    
                    
                    
                  
                
                
                @article{SM_2011_202_11_a4,
     author = {S. R. Safin},
     title = {Powers of sets in free groups},
     journal = {Sbornik. Mathematics},
     pages = {1661--1666},
     publisher = {mathdoc},
     volume = {202},
     number = {11},
     year = {2011},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_2011_202_11_a4/}
}
                      
                      
                    S. R. Safin. Powers of sets in free groups. Sbornik. Mathematics, Tome 202 (2011) no. 11, pp. 1661-1666. http://geodesic.mathdoc.fr/item/SM_2011_202_11_a4/
