Derivations with a hereditary domain, II
    
    
  
  
  
      
      
      
        
Studia Mathematica, Tome 130 (1998) no. 3, pp. 275-291
    
  
  
  
  
  
    
      
      
        
      
      
      
    Voir la notice de l'article provenant de la source Institute of Mathematics Polish Academy of Sciences
            
              The nilpotency of the separating subspace of an everywhere defined derivation on a Banach algebra is an intriguing question which remains still unsolved, even for commutative Banach algebras. On the other hand, closability of partially defined derivations on Banach algebras is a fundamental problem motivated by the study of time evolution of quantum systems. We show that the separating subspace S(D) of a Jordan derivation defined on a subalgebra B of a complex Banach algebra A satisfies $B[B ∩ S(D)]B ⊂ Rad_B(A)$ provided that BAB ⊂ A and $dim(Rad_J(A) ∩ ⋂_{n=1}^∞ B^n)  ∞$, where $Rad_J(A)$ and $Rad_B(A)$ denote the Jacobson and the Baer radicals of A respectively. From this we deduce the closability of partially defined derivations on complex semiprime Banach algebras with appropriate domains. The result applies to several relevant classes of algebras.
            
            
            
          
        
      @article{10_4064_sm_130_3_275_291,
     author = {A. Villena},
     title = {Derivations with a hereditary domain, {II}},
     journal = {Studia Mathematica},
     pages = {275--291},
     publisher = {mathdoc},
     volume = {130},
     number = {3},
     year = {1998},
     doi = {10.4064/sm-130-3-275-291},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/sm-130-3-275-291/}
}
                      
                      
                    A. Villena. Derivations with a hereditary domain, II. Studia Mathematica, Tome 130 (1998) no. 3, pp. 275-291. doi: 10.4064/sm-130-3-275-291
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