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From: "Bruno Luong" <b.luong@fogale.findmycountry>
Newsgroups: comp.soft-sys.matlab
Subject: Re: Dirac Delta Question
Date: Wed, 6 Feb 2013 15:59:08 +0000 (UTC)
Organization: FOGALE nanotech
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"Carl  S." wrote in message <ketqks$3vt$1@newscl01ah.mathworks.com>...

> 
> for example: C = [x(teta) y(teta)] and v(C, t). In this case, is the result of the dirac delta function of v meaningful ? If yes, what is its value ? a vector ?

A Dirac "function" (x is variable) is a distribution. The standard mathematic notation is "delta(x)", and it has zero value every where excepted at x=0 (its "support"), and integral of dirac is 1.

When one notes f=delta(x - 4), it is a composition of a dirac function with the function (x -> y:=x-4). Meanig that that f is the standard delta that is shifted so that the support is at x=4 (since when x=4, y = x-4=0) .

Many be you want to know g = delta(v(C,t)) (dirac of V), that mean a 2D "function" that has support at the set of points S = { v(C,t) = 0 } (+ some integral property). g is a distribution (function if you like), but is certainly not scalar or vector. 

Bruno