简介

My area of specialization is the theory of computation. Most of my published work prior to 1989 consists of fundamental contributions to the theory of finite semigroups, and the relationship of this theory to the study of finite automata and the languages they accept. Much of my research since then was devoted to computational complexity theory, particularly the interplay among small-depth circuit complexity, automata, and finite model theory. In the past several years, I have returned to work on the algebraic theory of automata, this time applied to tree automata and their connection to predicate and temporal logic.