One of the more significant achievements of twentieth century mathematics, especially from
the viewpoints of logic and computer science, was the work of Church, Gödel and Turing in …

We consider the following problem: given a labelled directed graph G and a regular
expression R, find all pairs of nodes connected by a simple path such that the concatenation …

Regular languages and finite automata are among the oldest topics in formal language
theory. The formal study of regular languages and finite automata can be traced back to the …

We study definability and complexity issues for automatic and/spl omega/-automatic
structures. These are, in general, infinite structures but they can be finitely presented by a …

Finite automata (FA's) are of fundamental importance in theory and in applications. The
following basic minimization problem is studied: Given a DFA (deterministic FA), find a …

Given an alphabet Σ, a (directed) graph G whose edges are weighted and Σ-labeled, and a
formal language L⊆Σ^*, the formal-language-constrained shortest/simple path problem …

Results on algorithmic problems on strings that are given in a compressed form via straight-
line programs are surveyed. A straight-line program is a context-free grammar that …

Finite automata are probably best known for being equivalent to right-linear context-free
grammars and, thus, for capturing the lowest level of the Chomsky-hierarchy, the family of …

We study definability problems and algorithmic issues for infinite structures that are finitely
presented. After a brief overview over different classes of finitely presentable structures, we …

Trust management is a form of distributed access control that allows one principal to
delegate some access decisions to other principals. While the use of delegation greatly …