From: &noreply@axelvogt.de   
      
   On 02.07.2014 19:35, Axel Vogt wrote:   
   > On 02.07.2014 14:34, paulandrewbird@gmail.com wrote:   
   >> On Tuesday, 1 July 2014 20:43:02 UTC+1, Axel Vogt  wrote:   
   >>> Do you have any (numerical) examples where your guess might be correct?   
   >>   
   >> My guess is simply based on the similarity to the quadratic integral:   
   >>   
   >> Integral[ exp(-A_ij x_i x_j )]dx^n = sqrt(pi^n / det(A) )   
   >   
   > If you mean the sum: for matrix = unit matrix then it is   
   > exp( x^2 + y^2 ) to be integrated over the plane, which   
   > is infinity, while det = 1. So at least you need sign   
   > conditions ( A = - Id will do)   
      
   PS: there is some issue with your formula   
      
            [-1     1]   
   for A = [        ]  having det = +1 that means to integrate   
            [ 0    -1]   
      
   exp( -x^2+x*y-y^2 ), resulting in Pi * 2/sqrt(3)   
      
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