Power expansion



Hi,
I have an expression which contains several parts in the following form:
(f(x[i])^(t*d[i,j]))^(1/d[i,j])
where the symbol d[i,j] is assumed (using assume()) to be greater or equal
to 1 for all i,j in [1,m].

How do I simplify this expression to get f(x)^t ?

thanks,
Paulo