THE ABC'S of Mice

This is the introductory half of a lecture given at the Association for Symbolic Logic Annual Meeting in Philadelphia in March, 2001. Our goal is to give logicians and advanced students who are unfamiliar with inner model theory a taste of what the subject is about at a level where it is possible to say something meaningful about the intuitions and proofs. At the same time, we wish to avoid overwhelming the reader, so we will leave out many well known closely related theorems and give only short proof sketches. Neither the results nor the proofs found here are due to the author. We will begin near the beginning but still touch on some modern aspects of the theory. The proofs and historical notes that we leave out can be found in the books and articles listed in the references. Our approach to the theory of 0# is a combination of that taken by Dodd in his book and by Steel in his lectures to students. Dodd's introduction is one of the author's favorite essays on inner model theory; another is the introduction to Martin-Steel [6]. In Section 2, we review the theory of 0# in a form that touches on some of the techniques that have been and continue to be generalized. These combine what is commonly called iteration and fine structure. In Section 3, we give a superficial description of what comes after 0#. Those interested in learning about more recent developments in inner model theory are encouraged to see the articles Lowe-Steel [5] and Steel [8], both of which are currently available online at http://www.math.berkeley.edu/~ steel.