Discrete Stochastic Processes and Optimal Filtering

Given that X is a real r.v. and Y = [ Y 1, , Y n is a real random vector, we assume that X and Y are independent and that the vector Z = ( X, Y 1, , Y n) admits a probability density f Z ( x, y 1, , y n).
In this section, we will use as required the notations ( Y 1, , Y n) or Y, ( y 1, , y n) or y.
Let us recall to begin with
.
We want, for all
and all
, to define and calculate the probability that X ? B knowing that Y 1 = y 1, , Y n = y n.
We denote this quantity P(( X ? B)( Y 1 = y 1) ? ?( Y n= y n)) or more simply P ( X ? B y 1, , y n). Take note that we cannot, as in the case of discrete variables, write:
The quotient here is indeterminate and equals
.
For j = 1 at n, let us note I j = [ y j, y j+h[
We...