Networks and their degree distribution, leading to a new concept of small worlds

Abstract

The degree distribution, referred to as the delta-sequence of a network is studied. Using the non-normalized Lorenz curve, we apply a generalized form of the classical majorization partial order. Next, we introduce a new class of small worlds, namely those based on degree centralities of networks. Similar to a previous study, small worlds are defined as sequences of networks with certain limiting properties. We distinguish between three types of small worlds: those based on the highest degree, those based on the average degree, and those based on the median degree. We show that these new classes of small worlds are different from those introduced previously based on the diameter of the network or the average and median distance between nodes. However, there exist sequences of networks that qualify as small worlds in both senses of the word, with stars being an example. Our approach enables the comparison of two networks with an equal number of nodes in terms of their small-worldliness. Finally, we introduced neighboring arrays based on the degrees of the zeroth and first-order neighbors and proved that for trees, equal neighboring arrays lead to equal delta-arrays.