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Martingale Representation and a Simple Proof of Logarithmic Sobolev Inequalities on Path Spaces	   
  
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Mireille  Capitaine, Universite Paul-Sabatier Elton P. Hsu, Northwestern University Michel  Ledoux, Universite Paul-Sabatier 			 | 
		  
	   
		
  
		
			 
				
					   
					   Abstract 
	We show how the Clark-Ocone-Haussmann formula for
Brownian motion on a compact Riemannian manifold put forward by 
S. Fang in his proof of the spectral gap inequality for the
Ornstein-Uhlenbeck operator on the path space can yield in a very simple 
way the logarithmic Sobolev inequality on the same space. By an appropriate
integration by parts formula the proof also yields in the same way a 
logarithmic Sobolev inequality for the path space equipped with a general 
diffusion measure as long as the torsion of the corresponding Riemannian 
connection satisfies Driver's total antisymmetry condition.
				   
 
  
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Full text: PDF
  Pages: 71-81
  Published on: December 15, 1997
 
  
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