On some systems of a~Hilbert space which are not bases
    
    
  
  
  
      
      
      
        
Vestnik Tomskogo gosudarstvennogo universiteta. Matematika i mehanika, no. 3 (2010), pp. 53-60
    
  
  
  
  
  
    
      
      
        
      
      
      
    Voir la notice de l'article provenant de la source Math-Net.Ru
            
              			In this paper we consider a sequence of normalized vectors $\{h_n\}^\infty_{n=1}$ in a Hilbert space $H$ such that the inner products $\langle h_i,h_j\rangle\ge\alpha$, $\alpha>0$, $i\ne j$, $i,j\in\mathbf N$. It is shown that this sequence of vectors is not a base in $H$.
			
            
            
            
          
        
      
                  
                    
                    
                    
                    
                    
                      
Keywords: 
Hilbert space, inner product, basis, complete sequences, angle between elements of a sequence.
                    
                  
                
                
                @article{VTGU_2010_3_a6,
     author = {T. E. Khmyleva and O. G. Ivanova},
     title = {On some systems of {a~Hilbert} space which are not bases},
     journal = {Vestnik Tomskogo gosudarstvennogo universiteta. Matematika i mehanika},
     pages = {53--60},
     publisher = {mathdoc},
     number = {3},
     year = {2010},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/VTGU_2010_3_a6/}
}
                      
                      
                    TY - JOUR AU - T. E. Khmyleva AU - O. G. Ivanova TI - On some systems of a~Hilbert space which are not bases JO - Vestnik Tomskogo gosudarstvennogo universiteta. Matematika i mehanika PY - 2010 SP - 53 EP - 60 IS - 3 PB - mathdoc UR - http://geodesic.mathdoc.fr/item/VTGU_2010_3_a6/ LA - ru ID - VTGU_2010_3_a6 ER -
T. E. Khmyleva; O. G. Ivanova. On some systems of a~Hilbert space which are not bases. Vestnik Tomskogo gosudarstvennogo universiteta. Matematika i mehanika, no. 3 (2010), pp. 53-60. http://geodesic.mathdoc.fr/item/VTGU_2010_3_a6/
