The boundary values of solutions of an elliptic equation
    
    
  
  
  
      
      
      
        
Sbornik. Mathematics, Tome 210 (2019) no. 12, pp. 1724-1752
    
  
  
  
  
  
    
      
      
        
      
      
      
    Voir la notice de l'article provenant de la source Math-Net.Ru
            
              			The paper is devoted to the study of the boundary behaviour of solutions of a second-order elliptic equation. Criteria are established for the existence of a boundary value of a solution of the homogeneous equation under the same conditions on the coefficients of the equation as were used to establish that the Dirichlet problem with a boundary function in $L_p$, $p>1$, has a unique solution. In particular, an analogue of Riesz's well-known theorem (on the boundary values of an analytic function) is proved: if a family of norms in the space $L_p$ of the traces of a solution on surfaces ‘parallel’ to the boundary is bounded, then this family of traces converges in $L_p$. This means that the solution of the equation under consideration is a solution of the Dirichlet problem with a certain boundary value in $L_p$. Estimates of the nontangential maximal function and of an analogue of the Luzin area integral hold for such a solution, which make it possible to claim that the boundary value is taken in a substantially stronger sense. 
Bibliography: 57 titles.
			
            
            
            
          
        
      
                  
                    
                    
                    
                        
Keywords: 
boundary value, Dirichlet problem.
Mots-clés : elliptic equation
                    
                  
                
                
                Mots-clés : elliptic equation
@article{SM_2019_210_12_a3,
     author = {A. K. Gushchin},
     title = {The boundary values of solutions of an elliptic equation},
     journal = {Sbornik. Mathematics},
     pages = {1724--1752},
     publisher = {mathdoc},
     volume = {210},
     number = {12},
     year = {2019},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_2019_210_12_a3/}
}
                      
                      
                    A. K. Gushchin. The boundary values of solutions of an elliptic equation. Sbornik. Mathematics, Tome 210 (2019) no. 12, pp. 1724-1752. http://geodesic.mathdoc.fr/item/SM_2019_210_12_a3/
