Consider a stochastic process Xt , tin1,2,3,..,N.
Xt is a Bernoulli variable and Pr(Xt=1)=p for all t.
The Autocovariance function gamma(|s−t|)=E[(Xt−p)(Xs−p)] is given
gamma(k)=frac12(|k−1|2H−2|k|2H+|k+1|2H).
For a constant Hin(0,1) This is the same autocovariance as for fractional gaussian noise (increments of the fractional brownian motion), and give a autocovariance which falls like a power law when k goes to infinity.
Let X and Y be process with the given properties, I am interested in the following probability distribution:
Prleft(sumNi=0XiYi=kright)
That is the distribution of the overlap of two such processes. For H=1/2 the process is not correlated and I have the simple result that Pr(XtYt)=p2, and that
Prleft(sumNi=0XiYi=kright)=Nchoosekp2k(1−p2)N−k.
But for Hneq1/2, I do not know how to deal with the long range correlation. Is there a way to proceed on this problem? I regret i never took a class in Stochastic Analysis, and I really hope the question makes sense. Any help or input would be highly appreciated.
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