We analyze fundamental characteristics of the inter-firm transaction network through the data of 800,000 Japanese firms. We find that there exists a hierarchical structure and a negative degree correlation in this transaction network. We also find that this undirected network is a scale-free...

We found hierarchical structure and negative degree correlation in firms' transaction network. The network consists of 800,000 Japanese firms. We also summarize other features of the network and discuss why studying network structure is important. We also found scale free distribution in...

We study evolutionary learning processes through social networks. We show that network heterogeneity, in particular scale-freeness, enhances social learning by studying a model in which an agent set on a network imitates the strategy only from the neighborhood. Further, in order to determine...

We study a coordination game in a network that indicates who plays with whom. A player chooses a strategy by logit choice. We show that in typical scale-free networks, one strategy always prevails by the neighborhood effect regardless of the values of parameters, while in regular networks, it...

We study a condition of favoring cooperation in a Prisoner's Dilemma game on complex networks. There are two kinds of players: cooperators and defectors. Cooperators pay a benefit b to their neighbors at a cost c, whereas defectors only receive a benefit. The game is a death-birth process with...

We analyze fundamental characteristics of the inter-firm transaction network through the data of 800,000 Japanese firms. We find that there exists a hierarchical structure and a negative degree correlation in this transaction network. We also find that this undirected network is a scale-free...

In International Economics, so-called gravity equation has been successful. In the present paper, we show that similar equation concerning transaction network holds well. The weight of transaction network among Japanese prefectures is explained by Sales-i*Sales-j/Distance-ij very well. The...