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Folding Deltas

• To: mathgroup at smc.vnet.net
• Subject: [mg56876] Folding Deltas
• From: baermic at yahoo.com
• Date: Mon, 9 May 2005 01:45:57 -0400 (EDT)
• Sender: owner-wri-mathgroup at wolfram.com

Can anyone help to verify in Mathematica the expression given by Rota
(http://xoomer.virgilio.it/maurocer/Text07.htm):

Convolution ( Sum of DiracDeltaFct ** Sum of DiracDeltaFct) == Sum
(DiracDeltaFct + Values).

I tied

Integrate[DiracDelta[t]  DiracDelta[t - 2] , {t, -3, 3} ]
which does not evaluate;
but

Integrate[DiracDelta[t]  DiracDelta[t - 2] , {t, -3, 1} ] +
Integrate[DiracDelta[t]  DiracDelta[t - 2] , {t, 1, 3} ] == 0
True

( I use ver 5.1 with W2k)

• Follow-Ups:
  • Re: Folding Deltas
    • From: Zhengji Li <zhengji.li@gmail.com>