An ERGM is a statistical model that can verify the existence of links in networks. In specific, an ERGM social selection model verifies various effects of variables related to attributes of actors. Estimates related to attribute variables represent the probability that particular attributes of...

It is important to investigate international relations at the system level because the system is the outcome of interaction among all states and trends in this system come back to affect individual states. In this study, we clearly demonstrate that the system of international relations is a...