First-order logic (FO) can express many algorithmic problems on graphs, such as the
independent set and dominating set problem parameterized by solution size. However, FO …

The regular separability problem asks, for two given languages, if there exists a regular
language including one of them but disjoint from the other. Our main result is decidability …

We study the computational complexity of existential Presburger arithmetic with (possibly
nested occurrences of) a Kleene-star operator. In addition to being a natural extension of …

Reachability problems in infinite-state systems are often subject to extremely high
complexity. This motivates the investigation of efficient overapproximations, where we add …

Multi-pushdown systems are a standard model for concurrent recursive programs, but they
have an undecidable reachability problem. Therefore, there have been several proposals to …

We study valence systems, finite-control programs over infinite-state memories modeled in
terms of graph monoids. Our contribution is a notion of bounded context switching (BCS) …

Valence systems are an abstract model of computation that consists of a finite-state control
and some storage mechanism. In contrast to traditional models, the storage mechanism is …

Certificates for automata in a hostile environment Page 1 Certificates for automata in a hostile
environment Sebastian Muskalla May 11, 2023 PhD defense Page 2 Table of contents Title …