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On the distribution of distances in recursive trees

Published online by Cambridge University Press:  14 July 2016

Robert P. Dobrow*
Affiliation:
National Institute of Standards and Technology
*
Postal address: Division of Mathematics and Computer Science, Northeast Missouri State University, Kirksville, MO 63501, USA.

Abstract

Recursive trees have been used to model such things as the spread of epidemics, family trees of ancient manuscripts, and pyramid schemes. A tree Tn with n labeled nodes is a recursive tree if n = 1, or n > 1 and Tn can be constructed by joining node n to a node of some recursive tree Tn–1. For arbitrary nodes i < n in a random recursive tree we give the exact distribution of Xi,n, the distance between nodes i and n. We characterize this distribution as the convolution of the law of Xi,j+1 and n – i – 1 Bernoulli distributions. We further characterize the law of Xi,j+1 as a mixture of sums of Bernoullis. For i = in growing as a function of n, we show that is asymptotically normal in several settings.

MSC classification

Type
Research Papers
Copyright
Copyright © Applied Probability Trust 1996 

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