My work has been primarily in model theory and to some degree in set theory. Model theory is the study of the construction and classification of structures inside some specific class of mathematical objects. It has both pure and applied sides which interact heavily. In applied model theory one takes some mathematical object in a given language, say the real numbers in the language of fields with exponentiation, and very carefully analyzes the sub-sets which are definable. This type of elimination theory has several applications in number theory and real algebraic geometry. An example of my work in this area is the first article listed below where we study certain model theoretic conditions in the context of varieties of algebras.

Pure or abstract model theory deals with several issues. The first, which sounds vaguely philosophical, is the question, "Is it possible to know if two structures are not isomorphic?'' This question is at the heart of classification theory. On the more practical side is stability theory which starts out by severely restricting the classes of structures one looks at so as to have a robust dimension theory available. Luckily common mathematical objects such as modules and algebraic groups are examples of stable structures.