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DBAR problem 1/1 https://en.wikipedia.org/wiki/DBAR_problem reference science, encyclopedia 2026-05-05T12:04:45.844723+00:00 kb-cron

The DBAR problem, or the

          ∂
          ¯
        
      
    
  

{\displaystyle {\bar {\partial }}}

-problem, is the problem of solving the differential equation

          ∂
          ¯
        
      
    
    f
    (
    z
    ,
    
      
        
          z
          ¯
        
      
    
    )
    =
    g
    (
    z
    )
  

{\displaystyle {\bar {\partial }}f(z,{\bar {z}})=g(z)}

for the function

    f
    (
    z
    ,
    
      
        
          z
          ¯
        
      
    
    )
  

{\displaystyle f(z,{\bar {z}})}

, where

    g
    (
    z
    )
  

{\displaystyle g(z)}

is assumed to be known and

    z
    =
    x
    +
    i
    y
  

{\displaystyle z=x+iy}

is a complex number in a domain

    R
    ⊆
    
      C
    
  

{\displaystyle R\subseteq \mathbb {C} }

. The operator

          ∂
          ¯
        
      
    
  

{\displaystyle {\bar {\partial }}}

is called the DBAR operator:

          ∂
          ¯
        
      
    
    =
    
      
        1
        2
      
    
    
      (
      
        
          
            ∂
            
              ∂
              x
            
          
        
        +
        i
        
          
            ∂
            
              ∂
              y
            
          
        
      
      )
    
  

{\displaystyle {\bar {\partial }}={\frac {1}{2}}\left({\frac {\partial }{\partial x}}+i{\frac {\partial }{\partial y}}\right)}

The DBAR operator is nothing other than the complex conjugate of the operator

    ∂
    =
    
      
        ∂
        
          ∂
          z
        
      
    
    =
    
      
        1
        2
      
    
    
      (
      
        
          
            ∂
            
              ∂
              x
            
          
        
        
        i
        
          
            ∂
            
              ∂
              y
            
          
        
      
      )
    
  

{\displaystyle \partial ={\frac {\partial }{\partial z}}={\frac {1}{2}}\left({\frac {\partial }{\partial x}}-i{\frac {\partial }{\partial y}}\right)}

denoting the usual differentiation in the complex

    z
  

{\displaystyle z}

-plane. The DBAR problem is of key importance in the theory of integrable systems, Schrödinger operators and (together with a jump condition) generalizes the RiemannHilbert problem.

== Citations ==

== References == Ablowitz, Mark J.; Fokas, A. S. (2003). Complex Variables: Introduction and Applications. Cambridge University Press. pp. 516, 598626. ISBN 978-0-521-53429-1. Haslinger, Friedrich (2014). The d-bar Neumann Problem and Schrödinger Operators. Walter de Gruyter GmbH & Co KG. ISBN 978-3-11-031535-6.[1] Konopelchenko, B. G. (2000). "On dbar-problem and integrable equations". arXiv:nlin/0002049.