On the work of Andrzej Ehrenfeucht in model theory -- Syntax vs. semantics on finite structures -- Expressive power of unary counters -- Some strange quantifiers -- Pebble games in model theory -- An interpretive isomorphism between binary and ternary relations -- Vagueness - A rough set view -- Ehrenfeucht games, the composition method, and the monadic theory of ordinal words -- Monadic second order logic and node relations on graphs and trees -- Approximating the volume of general Pfaffian bodies -- Complement-equivalence classes on graphs -- On compact directed acyclic word graphs -- Metric entropy and minimax risk in classification -- Of periods, quasiperiods, repetitions and covers -- Combinatorics of standard Sturmian words -- Compactness of systems of equations on completely regular semigroups -- Decision problems concerning algebraic series with noncommuting variables -- Associative shuffle of infinite words -- Constructing sequential bijections -- Rewriting rules for synchronization languages -- DNA sequence classification using DAWGs -- DNA computing: Distributed splicing systems.