Processing math: 100%

Thursday, 25 October 2007

pr.probability - Conditional expectation of convolution product equals..

Assuming Omega has the structure for defining convolutions I don't think it is ever an algebra homomorphism. Take X to be supported on mathcalGc, i.e. take some set of non-zero measure in mathcalGc and let X be a function whose support lies in that set, then E(XastY|mathcalG)neq0 but E(X|mathcalG)=0 so E(X|mathcalG)astE(Y|mathcalG)=0.



Edit: Scratch what I said. I was confusing sub-sigma-algebra with sub-algebra of random variables and even in the finite case my statement is completely incorrect. In almost every instance E(X|mathcalG) will not be zero as Jonas points out in the comments.

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