From: Ian G. <ia...@ma...> - 2003-05-06 18:39:36
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On Tuesday 06 May 2003 17:53, Jens Axel S=F8gaard wrote: > >(And after all the Dirac delta is a statistical distribution). > > I'm not quite sure that's right - a statistical distribution is still a > function (isn't it?). Probably not quite expressed correctly, I think I should have said the de= lta=20 measure is statistical distribution. The idea being that continuous=20 probabilities are defined better by measures than functions. The uniform=20 distribution f(x) =3D 1 for 0 < x < 1, the actual value of the function a= t=20 point isn't really statistical meaningful only it's integral over subsets= of=20 R is - just like the values of delta(x) aren't always meaningful but the=20 integrals are. > >But then that is maths in a nutshell, "assume this and what interestin= g > > things drop out." Though for delta (I'm fairly sure that) you can ass= ume > > more fundamental things and it's existence, integrability etc. drops = out. > > It's not just playing with axioms. You can make intermediate (ary?) > calculations involving delta, > and in the end all the deltas cancel out, and you are left with an > ordinary function as a result. > One can use this to study certain kinds of differential equations. Agreed. |