Central limit theorems for fringe trees in patricia tries

We give theorems about asymptotic normality of general additive functionals on patricia tries, derived from results on tries. These theorems are applied to show asymptotic normality of the distribution of random fringe trees in patricia tries. Formulas for asymptotic mean and variance are given. The proportion of fringe trees with keys is asymptotically, ignoring oscillations, given by (1−())/( +)(−1) with the source entropy , an entropy-like constant , that is in the binary case, and an exponentially decreasing function (). Another application gives asymptotic normality of the independence number and the number of -protected nodes