Research Interests
Harmonic Analysis on Groups
- Representation theory of finite groups
- Finite Gelfand pairs
- Association schemes
- Discrete potential theory
- Random walks on groups and graphs
- Spectral Graph Theory
- Representation Theory (Locally compact groups, Haar measures, compact groups)
Geometric and Combinatorial Group Theory
- Asymptotic Group Theory (growth functions, the Grigorchuk group, the Thompson group F)
- Amenability (Folner functions, isoperimetric functions)
- Sofic groups
- Surjunctive groups (Gottschalk conjecture)
- Dehn's decidability probles (Word Problem, Dehn's Algorithm, Subgroup Membership Problem)
- Cellular automata on groups
- Group algebras (Kaplansky's conjectures)
Functional Analysis
- Amenability and means on groups
- Operator Algebras (C*-algebras, von Neumann algebras, subfactors)
- Representation Theory (Locally compact groups, Haar measures, compact groups)
- Spectral Graph Theory
Ergodic Theory and Dynamical Systems
- Ergodic theorems
- Symbolic Dynamics and Cellular automata on groups
- Algebraic Dynamical Systems (a la K. Schmidt)
- Topological Dynamics; entropy
Probability Theory
- Finite Markov chains
- Random walks on groups and graphs
- System Theory
Theoretical Computer Science
- Formal languages (regular languages, linear languages, context-free languages, languages associated with groups)
- Automata theory (finite-state automata, push-down automata, Turing machines, Mealy machines)
- Computability and Recursion Theory
- Cellular automata
Logics and Model Theory
- First order Logic and Model Theory
- Second order Monadic Logic
- Computability