Some extremal problems for martingale transforms. I
    
    
  
  
  
      
      
      
        
Zapiski Nauchnykh Seminarov POMI, Investigations on linear operators and function theory. Part 51, Tome 527 (2023), pp. 5-53
    
  
  
  
  
  
    
      
      
        
      
      
      
    Voir la notice de l'article provenant de la source Math-Net.Ru
            
              			With this paper, we begin a series of studies of extremal problems for estimating the distributions of martingale transforms of bounded martingales. The Bellman functions corresponding to such problems are pointwise minimal diagonally concave functions on a horizontal strip, satisfying certain given boundary conditions. We describe the basic structures that arise in the construction such functions and present a solution in the case \break of asymmetric boundary conditions and a sufficiently small width of the strip.
			
            
            
            
          
        
      @article{ZNSL_2023_527_a0,
     author = {V. I. Vasyunin and P. B. Zatitskii},
     title = {Some extremal problems for martingale transforms. {I}},
     journal = {Zapiski Nauchnykh Seminarov POMI},
     pages = {5--53},
     publisher = {mathdoc},
     volume = {527},
     year = {2023},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZNSL_2023_527_a0/}
}
                      
                      
                    V. I. Vasyunin; P. B. Zatitskii. Some extremal problems for martingale transforms. I. Zapiski Nauchnykh Seminarov POMI, Investigations on linear operators and function theory. Part 51, Tome 527 (2023), pp. 5-53. http://geodesic.mathdoc.fr/item/ZNSL_2023_527_a0/