Algebraic Combinatorics; in particular,
theory of association schemes; schemes are combinatorial configurations
which may be viewed as generalized groups and generalized distance-regular
graphs. The theory provides a foundation of an algebraic approach to
error-correcting codes and combinatorial designs.
Interests also lie in other various
combinatorial and algebraic objects, such as, combinatorial designs,
distance-regular graphs, codes, matrix theory, extremal set theory,
cryptography, classical groups, permutation groups, loops, partially
ordered sets, group characters and representations.