Harmonic Maps in General Relativity.
        
    
   
            
                
                    
                        
    
          
 Orateur 
      YAMADA, Sumio
     
                
                
            
    
        
            
        
            Résumé
             In 1917, shortly after Einstein had announced his master equation for general relativity, H. Weyl characterized the Schwarzschild metric, which is the first nontrivial solution to the Einstein equation, by a harmonic function.  Since then, the solutions to the Einstein equation with a certain set of symmetries are identified with elliptic variational problems, in particular the harmonic map equation.  With Marcus Khuri, Gilbert Weinstein and Martin Reiris, we have constructed a new set of stationary solutions to the  higher dimensional vacuum Einstein equations, which contains non-spherical event horizons, as well as gravitational solitons, which contains no blackholes, yet geometrically nontrivial.  
        
        
    
    
Orateur
YAMADA, SumioRésumé
 In 1917, shortly after Einstein had announced his master equation for general relativity, H. Weyl characterized the Schwarzschild metric, which is the first nontrivial solution to the Einstein equation, by a harmonic function.  Since then, the solutions to the Einstein equation with a certain set of symmetries are identified with elliptic variational problems, in particular the harmonic map equation.  With Marcus Khuri, Gilbert Weinstein and Martin Reiris, we have constructed a new set of stationary solutions to the  higher dimensional vacuum Einstein equations, which contains non-spherical event horizons, as well as gravitational solitons, which contains no blackholes, yet geometrically nontrivial.