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We analyze whether random network formation processes, such as preferential attachment, can emerge as the outcome of strategic behaviour. We represent network formation as an extensive game in which players sequentially form links as they enter the network. In this setting, we investigate under which conditions subgame perfect equilibria of the game are observationally equivalent with random network formation process. We put forward two structural conditions that are necessary in this respect. First, players must have some form of imperfect information as randomization is purposeful only if its realization is not perfectly observed by the other players. Second, there must be some form of competition between a player and its successors: a player has incentives to reduce the information available to its successors only to the extent that their objectives are in opposition. Accordingly, we put forward a class of games where players compete with their predecessors and their successors for the costs and benefits induced by link formation and show that subgame perfect equilibria of this game are observationally equivalent with random network formation process. In particular, when linkage costs are inversely proportional to the degree of a node, equilibrium play induces a preferential attachment process. This provides a positive answer to the question of the existence of strategic foundations for preferential attachment. However the very specific conditions requiredfor the observational equivalence to hold suggest that preferential attachment can be explained by strategic considerations only in a limited number of situations. [ABSTRACT FROM AUTHOR]

In this paper, we aim at investigating various aspects of countries’ behaviour during the coronavirus pandemic period. By means of a multiplex network, we simultaneously consider government responses based on COVID-19 infections, Stringency Index, international trade and international air mobility data, to detect clusters of countries that showed a similar reaction to the pandemic. We propose a new methodological approach based on the Estrada communicability for identifying communities on a multiplex network, based on a two-step optimization process. At first, we determine the optimal inter-layer weight between levels by minimizing a distance function. Hence, the optimal weight is used to detect the communities on each layer. Our findings show that this new approach to community detection on a multiplex network provides additional insights with respect to the same procedure performed on layers separately. Indeed, clusters in the multiplex network benefit from a higher cohesion, as they are detected taking into account the mutual influence of the other networks. [ABSTRACT FROM AUTHOR]

In this paper, we show that a comprehensive analysis of temporal network evolution requires to consider measures of non-structural changes, in addition to classical topological indicators. We employ a recently proposed measure of non-structural dynamics, together with other structural indicators, to analyze the time evolution of three subnetworks, extracted from the Italian corporate board network. Consistently with recent literature, we show that, to different extent, both structural and non-structural changes are present and must be accounted for, in order to get a satisfactory description of their temporal evolution. [ABSTRACT FROM AUTHOR]

This paper addresses the issue of measuring temporal dynamics of complex socio-economic relational systems, represented as time-dependent networks. Network dynamics is first splitted into a structural component, accounting for changes in the network topology, and a non-structural component, accounting for permutation of vertex labels. A quantitative measure of the dynamics and its components is then proposed and it is shown how it can be used to investigate and interpret the time evolution of networks. A real example is discussed, pertaining to the dynamics of a subnetwork of the Italian corporate board network. [ABSTRACT FROM AUTHOR]