where D(vi,v) is given by Equation (6.1e), and N(u,v) is defined by a surface or a 

 line integral of the type 



i.v) . J 



N(y,v) = I exp[z(y^+v^)"'-''^+i(xU+yV)]A(x)da,dxdy,d£ (6.5a) 



h,a . ,c 



If a small positive number is used for the parameter e, the function D(y,v) has no 

 real root, and the integral (6.5) can be evaluated without difficulty in principle. 



25 



