Re: Defining Real Expressions

*To*: mathgroup at smc.vnet.net*Subject*: [mg8535] Re: Defining Real Expressions*From*: Raya Firsov-Khanin <raya at mech.ed.ac.uk>*Date*: Sat, 6 Sep 1997 23:16:07 -0400*Sender*: owner-wri-mathgroup at wolfram.com

Marco Beleggia wrote: <I must evaluate an Integral in which I'd like to assign real values to <some parameters, but I don't know how to do that. <For example, in the following integral (a Fourier Transform): <f[x_,p_]=Integrate[y/(x^2+y^2) Exp[-I p y],{y,-Infinity,Infinity}], <p should be a real parameter. The output given by Mathematica is <conditioned to Im[p]==0, such as If[Im[p]==0,....,....], which is not <easy to handle, and I'd like to avoid this complication. <Is it possible ? The simplest way to deal with this is to declare p/:Im[p]=0 Then, f[x, p] will give you an answer (if Arg[x^2]!=\[Pi]). ------- Raya Khanin