Re: Apparent error integrating product of DiracDelta's

*To*: mathgroup at smc.vnet.net*Subject*: [mg91998] Re: Apparent error integrating product of DiracDelta's*From*: Michael Mandelberg <mmandelberg at comcast.net>*Date*: Tue, 16 Sep 2008 19:24:57 -0400 (EDT)*References*: <gag2lg$39k$1@smc.vnet.net> <gal3ht$dv1$1@smc.vnet.net>

On Sep 15, 3:40 am, "Nasser Abbasi" <n... at 12000.org> wrote: > "Michael Mandelberg" <mmandelb... at comcast.net> wrote in message > > news:gag2lg$39k$1 at smc.vnet.net... > > > How do I get: > > > Integrate[DiracDelta[z- x] DiracDelta[z- y], {z-Infinity, Infinity}= ] > > > to give DiracDelta[x-y] as the result? Currently it gives 0. I ha= ve > > all three variable assumed to be Reals. I am using 6.0.0. > > > Thanks, > > Michael Mandelberg > > I think you have synatx error in the limit part. I assume you mean to wri= te > {z, -Infinity,Infinity} > > Given that, I think zero is the correct answer. When you multiply 2 de= ltas > at different positions, you get zero. Integral of zero is zero. > > Nasser Thanks for pointing out the typo, yes, there was a comma missing. However, I disagree with your conclusion. Who says 'x' and 'y' are different?