Convergence of Fourier series in classical systems
    
    
  
  
  
      
      
      
        
Sbornik. Mathematics, Tome 206 (2015) no. 7, pp. 941-979
    
  
  
  
  
  
    
      
      
        
      
      
      
    Voir la notice de l'article provenant de la source Math-Net.Ru
            
              			The following results are proved:
there exists an integrable function such that any subsequence of the Cesàro means of negative order of the Fourier series of this function diverges almost everywhere;
the values of an arbitrary integrable function can be changed on a set (independent of this function) of arbitrarily small measure so that the Fourier series with respect to both the Franklin system and the Haar system of the
‘modified’ function will be absolutely convergent almost everywhere on $[0,1]$;
there exists a continuous function which features an unremovable absolute divergence.
 Bibliography: 47 titles.
			
            
            
            
          
        
      
                  
                    
                    
                    
                        
Keywords: 
Fourier series, classical systems, Cesàro means, almost everywhere convergence, convergence in the norm, absolute convergence.
                    
                    
                    
                  
                
                
                @article{SM_2015_206_7_a2,
     author = {L. N. Galoyan and M. G. Grigoryan and A. Kh. Kobelyan},
     title = {Convergence of {Fourier} series in classical systems},
     journal = {Sbornik. Mathematics},
     pages = {941--979},
     publisher = {mathdoc},
     volume = {206},
     number = {7},
     year = {2015},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_2015_206_7_a2/}
}
                      
                      
                    L. N. Galoyan; M. G. Grigoryan; A. Kh. Kobelyan. Convergence of Fourier series in classical systems. Sbornik. Mathematics, Tome 206 (2015) no. 7, pp. 941-979. http://geodesic.mathdoc.fr/item/SM_2015_206_7_a2/
