About me

My name is Lukas Fleischer. I was born on March 6th, 1990 and I am currently living near Stuttgart, Germany. I am a research assistant at the FMI, University of Stuttgart. My primary research areas are automata theory, formal languages, semigroup theory, algorithms, computational complexity and formal verification. An up-to-date list of my publications can be found below. Alternatively, you can check our institute website or DBLP.

I actively contribute to a variety of open source software. Please scroll down for a (not necessarily complete) list of projects I am involved in.

I am also interested in machine learning, artificial intelligence, sustainability and everything health and fitness related.

Short CV

2015-present PhD Candidate and Research Assistant (FMI, University of Stuttgart)
2013-2015 M.Sc. Computer Science (University of Stuttgart)
2010-2013 B.Sc. Computer Science (University of Stuttgart)
2000-2009 High School (Gymnasien im Ellental, Bietigheim-Bissingen)
1996-2000 Elementary School (Grundschule im Sand, Bietigheim-Bissingen)


Conference Articles

  • Lukas Fleischer. On the Complexity of the Cayley Semigroup Membership Problem. CCC 2018 (accepted).
  • Lukas Fleischer and Manfred Kufleitner. The Intersection Problem for Finite Monoids. STACS 2018.
  • Volker Diekert and Lukas Fleischer. Church-Rosser Systems, Codes with Bounded Synchronization Delay and Local Rees Extensions. WORDS 2017.
  • Lukas Fleischer and Manfred Kufleitner. Green's Relations in Finite Transformation Semigroups. CSR 2017.
  • Lukas Fleischer and Manfred Kufleitner. Operations on Weakly Recognizing Morphisms. DCFS 2016.
  • Lukas Fleischer and Manfred Kufleitner. Efficient Algorithms for Morphisms over Omega-Regular Languages. FSTTCS 2015.
  • Lukas Fleischer, Manfred Kufleitner and Alexander Lauser. Block Products and Nesting Negations in FO2. CSR 2014.

Journal Articles

  • Lukas Fleischer and Manfred Kufleitner. Green's Relations in Deterministic Finite Automata. Theory of Computing Systems. Springer, 2018.
  • Lukas Fleischer, Manfred Kufleitner and Alexander Lauser. The Half-Levels of the FO2 Alternation Hierarchy. Theory of Computing Systems, volume 61, issue 2, pp 352–370. Springer, 2017.

Open Source Projects

Arch Linux

As an Arch Linux Trusted User and Developer, I am leading the development of the Arch User Repository web interface and maintaining the Arch Linux projects page as well as roughly 200 packages.


I am the current maintainer of calcurse, a powerful command-line based calendar program.


I am a regular contributor to cgit, a hyperfast web frontend for Git repositories written in C.


In late 2017, I started co-maintaining jpeg-archive, a utility to compress JPEG images for long-term storage without sacrificing perceived visual quality.

Other Projects and Contributions

aurdupes is a Python script that can be used to find duplicate packages in pacman databases and the Arch User Repository.

cdlib-eject is a lightweight C program to control Dacal CD Library II devices.

Every now and then, I contribute to other projects, such as

  • alot, a terminal-based mail user agent,
  • the version control system Git,
  • libfaketime, which can be used to modify the system time for a single application,
  • the package manager pacman,
  • the password manager pass,
  • pygit2, and
  • xwax, an open-source Digital Vinyl System (DVS) for Linux.

I am known as lfleischer on most platforms. My GitHub user name is lfos.


Please do not send any email to Lukas Fleischer <spmtrp@lfos.de>.

Feel free to send an email to Lukas Fleischer <lfleischer@lfos.de>. My public key can be found on common PGP key servers. The key fingerprint is 2E36 D862 0221 482F C45C B7F2 A917 6475 9326 B440.