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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?


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