A típustér fogalma és tulajdonságai = The Idea and the Features of Type Space

Several game theoretical topics require the analysis of hierarchical beliefs, particularly in incomplete information situations. For the problem of incomplete information, Hars´anyi suggested the concept of the type space. Later Mertens & Zamir gave a construction of such a type space under topological assumptions imposed on the parameter space. The topological assumptions were weakened by Heifetz, and by Brandenburger & Dekel. In this paper we show that at very natural assumptions upon the structure of the beliefs, the universal type space does exist. We construct a universal type space, which employs purely a measurable parameter space structure. We divided this work into two parts. In the first part we introduce the main ideas and features of type space. We follow Heifetz & Samet, however we take some steps out of their work. We also introduce an example to present the usefulness of type space. In the second part we present a complete universal type space, which contains the works of Mertens & Zamir, Heifetz, and Brandenburger & Dekel as a special case. The two parts of this work can be read separately, therefore there are some minor parallelism in this paper.