問題状況の主観的評価に基づく意思決定:相互認識のあるハイパーゲームとその応用

抄録

The purpose of the paper is two-fold: The first is to develop a formal argument on the hypergame with inter-identification and the second is to apply the theoretical argument to a real problematic situation not only for demonstrating the validity of the theoretical results but also for obtaining suggestions for the problem improvement. The hypergames analysis is one of what we call soft systems approaches and was originally proposed to analyze complex decision situations involving several participants by extending the game theory. The hypergame, different from the usual game analysis, explicitly assumes that the participants in the same decision situation perceive it differently because of diversity of their value systems and of the ways of perception. We first reformulate concepts of the simple hypergames rigorously and define the hypergames with inter-identification as a system consisting of simple hypergames connected by the mutual identificcation. We then propose a definition of solutions for them. Based on the formulation, the paper derives existence conditions of the solutions. The conditions tell us whether or not the hypergame with inter-identification emerges new solutions that have not existed in the simple hypergames. Finally we apply the framework to a realistic problem, i.e., Japan-US trade imbalance problem to demonstrate the validity of the derived theoretical results as well as to obtain some suggestions to improve the problematic situation.