A variation on a~theme of Caffarelli and Vasseur
    
    
  
  
  
      
      
      
        
Zapiski Nauchnykh Seminarov POMI, Boundary-value problems of mathematical physics and related problems of function theory. Part 40, Tome 370 (2009), pp. 58-72
    
  
  
  
  
  
    
      
      
        
      
      
      
    Voir la notice de l'article provenant de la source Math-Net.Ru
            
              			Recently, using DiGiorgi-type techniques, Caffarelli and Vasseur [1] showed that a certain class of weak solutions to the drift diffusion equation with initial data in $L^2$ gain Hölder continuity provided that the BMO norm of the drift velocity is bounded uniformly in time. We show a related result: a uniform bound on BMO norm of a smooth velocity implies uniform bound on the $C^\beta$ norm of the solution for some $\beta>0$. We use elementary tools involving control of Hölder norms using test functions. In particular, our approach offers a third proof of the global regularity for the critical surface quasi-geostrophic (SQG) equation in addition to [5] and [1]. Bibl. – 6 titles.
			
            
            
            
          
        
      @article{ZNSL_2009_370_a3,
     author = {A. Kiselev and F. Nazarov},
     title = {A variation on a~theme of {Caffarelli} and {Vasseur}},
     journal = {Zapiski Nauchnykh Seminarov POMI},
     pages = {58--72},
     publisher = {mathdoc},
     volume = {370},
     year = {2009},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/ZNSL_2009_370_a3/}
}
                      
                      
                    A. Kiselev; F. Nazarov. A variation on a~theme of Caffarelli and Vasseur. Zapiski Nauchnykh Seminarov POMI, Boundary-value problems of mathematical physics and related problems of function theory. Part 40, Tome 370 (2009), pp. 58-72. http://geodesic.mathdoc.fr/item/ZNSL_2009_370_a3/