Abstract :
In this paper we explore a connection between descriptive set theory and inner model theory. From descriptive set theory, we will take a countable, definable set of reals, A. We will then show that View the MathML source, where View the MathML source is a canonical model from inner model theory. In technical terms, View the MathML source is a “mouse”. Consequently, we say that A is a mouse set. For a concrete example of the type of set A we are working with, let ODnω1 be the set of reals which are ∑n definable over the model Lω1 (R), from an ordinal parameter. In this paper we will show that for all n ⩾ 1, ODnω1 is a mouse set. Our work extends some similar results due to D.A. Martin, J.R. Steel, and H. Woodin. Several interesting questions in this area remain open.
