DBLP · Google Scholar · ORCID · ResearchGate · ArXiv

Welcome to my homepage! My name ist Stefan Hoffmann and I am a PhD student in Trier under the supervision of Prof. Dr. Henning Fernau.

My interests circle around the areas of finite automata theory, more specifically problems of synchronization and state complexity, and formal language theory, in particular commutative languages and the shuffle operation. Furthermore, I am interested in group theory and algebra and applications of it to above mentioned fields of study. Sometimes I dabble into omega languages and (general) topology. Recently, I got more involved into computational complexity, in particular parameterized complexity.

Research interest keywords: automata, formal language theory, synchronization, (finite) permutation group theory, permutation automata, group languages, parameterized complexity, computational complexity, shuffle product, partial commutativity, commutative languages, state complexity, omega languages.

My Erdös number is three (via Henning Fernau or Ludwig Staiger, both two).

Contact: hoffmanns (at) informatik (dot) uni (hyphen) trier (dot) de

For some papers, I have put up a link to an errata - unfortunately mistakes happen, but up to now they were all minor and I mostly fixed them in the latest arXiv version (indicated in the corresponding errata file). If you spot any mistakes or unclear formulations, please do not hesitate to tell me!

In preparation:

  • New Characterizations of Primitive Permutation Groups with Applications to Synchronizing Automata (Journal Version)
  • Automata Containing a Cyclic Permutation and Having Maximal State Complexity for the Set of Synchronizing Words (Journal Version)
  • State Complexity Bounds for the Commutative Closure of Group Languages (Journal Version)
  • Constrained Synchronization and Commutative Languages (Journal Version)
  • Commutative Regular Languages - Properties and State Complexity (Journal Version)

Preprints:

  • Henning Fernau, Stefan Hoffmann, Michael Wehar, Finite Automata Intersection Non-Emptiness: Parameterized Complexity Revisited
    arXiv version

Published:

2021

2020

2019

2017

2015