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Re: Apparent error integrating product of DiracDelta's

  • To: mathgroup at smc.vnet.net
  • Subject: [mg91962] Re: Apparent error integrating product of DiracDelta's
  • From: "Nasser Abbasi" <nma at 12000.org>
  • Date: Mon, 15 Sep 2008 03:40:55 -0400 (EDT)
  • References: <gag2lg$39k$1@smc.vnet.net>
  • Reply-to: "Nasser Abbasi" <nma at 12000.org>

"Michael Mandelberg" <mmandelberg 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 have
> 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 write 
{z, -Infinity,Infinity}

Given that, I think zero is the correct answer.  When you multiply 2 deltas 
at different positions, you get zero. Integral of zero is zero.

Nasser






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