Network theory

About: Network theory is a research topic. Over the lifetime, 2257 publications have been published within this topic receiving 109864 citations.

Was there a network of Roman Mithraists

Abstract: Folklorist and anthropologist Andrew Lang has identified a tendency for the homonymy of gods to be characteristic of “the mythological period of all nations”.1 In contrast to the phenomenology of religion, which posits an essentialized “sacrality” underlying the various theographies, a perennial history of religions’ question is that of the specific relationship(s) between deities sharing a common name. While this problem of the relationship of homonymous deities is, perhaps, most generally familiar from Greek polytheism,2 that between the various incarnations of the IndoEuropean Mithra has recently been reintroduced to modern scholarship.3 Already from the second millennium BC (c. 1500-1200 BC), a solar deity with the name of Mitra is prominent in the Hindu pantheon of the Indian Rig Veda as guarantor of friendship and contract, and, contemporaneously (c. 1400 BC), as witness to an inscribed peace treaty between the Hittites and their neighbors. A Mithra is later attested in the Persian Avestas from c. sixth century BC as a divine solar protector of truths, covenants and oaths. Subsequently, an initiatory cult of a Mithras Sol Invictus is documented by archaeological remains from the end of the first century AD throughout the expanse of the Roman Empire.4 Might these homonymous Indo-European deities be related? If so, what might be their historical connection(s)?

The Italian Corporate System: SOEs, Private Firms and Institutions in a Network Perspective (1952-1983)

Abstract: How did business networks among Italian firms evolve over time? We address this question by analyzing the Italian corporate boards network in four years (1952, 1960, 1972, 1983) with network theoretical methods. We find some typical properties of these networks, such as sparsity and connectedness in the same large network component. At the same time, clustering and assortativity are relatively high and stable, while we observe, over time, an increase of the average distance coupled with a decrease of density and of the relative size of the largest component. This is an indication of a rarefaction of connections which is detected also in other national systems. In order to seek the determinants of this phenomenon, we perform a panel regression for the average nodal degree, finding that rarefaction is mostly related to a genuine time trend and only partially to cross-sectional variables. We argue that a possible explanation is a significant increase of concentration which we observe in our dataset, consistently with historical evidence. The network shows a substantial stability in some structures, such as core-periphery subdivision. Looking at the main actors we find a persistent centrality of banks and insurances, as well as of State Owned Enterprises (SOEs). These play a growing role in the community structure of the network, while communities themselves become more and more diversified by sector.

Spectral Functional-Digraph Theory, Stability, and Entropy for Gene Regulatory Networks

Abstract: Spectral graph theory is an indispensable tool in the rich interdisciplinary field of network science, which includes as objects ordinary abstract graphs as well as directed graphs such as the Internet, semantic networks, electrical circuits, and gene regulatory networks (GRN). However, its contributions sometimes get lost in the code, and network theory occasionally becomes overwhelmed with problems specific to undirected graphs. In this paper, we will study functional digraphs, calculate the eigenvalues and eigenvectors of their adjacency matrices, describe how to compute their automorphism groups, and define a notion of entropy in terms of their symmetries. We will then introduce gene regulatory networks from scratch, and consider their phase spaces, which are functional digraphs describing the deterministic progression of the overall state of a GRN. Finally, we will redefine the stability of a GRN and assert that it is closely related to the entropy of its phase space.