December 2022: My essay on fairness/equity in AI (Gerechte Künstliche Intelligenz) has been
published by the Academy of Sciences and Humanities in Hamburg as part of the essay series on
fairness/equity (in german).
November 2022: The National Research Data Infrastructure for and with Computer Science (NFDIxCS) has been accepted for funding by German Gemeinsame Wissenschaftskonferenz (GWK); see also the press release (in german).
October 2022: I have been awarded a Fellowship of the Academy of Sciences in Hamburg (Akademie der Wissenschaften in Hamburg), Germany, as part of their Young Academy Fellows program, fostering interdisciplinary research and scientific dialog. See also the press release.
August 2022: The Workshop on Practical Aspects of Automated Reasoning (PAAR 2022) took place on August 11 - 12 in Haifa, Israel, co-located with IJCAR/FLoC. We had a great program of 14 contributed talks and two invited talks, and two special sessions on the COST action EuroProofNet. Thanks a lot to all participants for the great talks and interesting discussions! Proceedings have been published at CEUR-WS.org.
July 2022: The AuReLeE conclusion workshop, with eight invited keynotes by experts from automated reasoning and/or normative and deontic logics, took place from July 15 - July 22 at the University of Luxembourg. Thank you for the productive working sessions and discussions!
June 2022: The first deadline for abstract of Deduktionstreffen 2022 is approaching. Looking forward to see your submissions!
April 2022: Claudia Schon's and my workshop proposal for the next Deduktionstreffen at the KI 2022 has been accepted. Deduktionstreffen 2022 will finally again be implemented as a colloquial in-place meeting at Trier. Details will follow soon.
March 2022: I was appointed as German Informatics Society ambassador (GI-Botschafter) to the University of Greifswald.
February 2022: The conference paper "Von Objekt- und Meta-Ebenen: Analyse der Softwareanforderungen computergestützter juristischer Entscheidung" (On object and meta levels: Analysis of software requirements for computer-assisted legal decisions), presented at the 25. Internationales Rechtsinformatik Symposion (International Legal Informatics Symposium, IRIS 2022), was selected as one of the Top 10 Papers by the LexisNexis best paper award jury. The paper is co-written by Axel Adrian, Max Rapp (FAU University of Erlangen-Nuremberg) and myself.
January 2022: Claudia Schon and myself were re-elected as spokespersons of the SIG deduction systems (Fachgruppe Deduktionssysteme) of the AI section of the German Informatics Society (GI). Thanks a lot for your trust!
January 2022: I started a new position as assistant professor for computer science at the University of Greifswald.
January 13, 2023: World-Logic-Day lecture in Greifswald by Reinhard Kahle (Tübingen). (co-organizer)
May 14-17, 2023: The 36th International FLAIRS Conference, Florida, USA (hybrid).
July 1-4, 2023: 29th international Conference on Automated Deduction (CADE-29), Rome, Italy. (PC member)
This is the personal homepage of Alexander Steen. I am a Juniorprofessor (this is roughly equivalent to an assistant professor position) at the Institute of Mathematics and Computer Science of the University of Greifswald. I'm working on computational logic, automated reasoning and theoretical computer science. I'm the lead developer of the automated theorem prover Leo-III, a reasoning system for classical higher-order logic (HOL) and further expressive, non-classical logics (including higher-order modal logics and deontic logics) as well as further smaller software artifacts. My ORCID ID is 0000-0001-8781-9462.
My current research interests include theory and practice of higher-order reasoning, including efficient data structures for higher-order theorem provers, and related implementation techniques. Furthermore, I'm interested in practical aspects and applications of logics and formal methods in computer science, mathematics and philosophy. Also, I like functional programming (e.g. in Haskell). A research profile (self-portrayal) about my recent work was published by the it - Information Technology journal: See doi:10.1515/itit-2019-0001.
In my freetime, I'm a bass singer in a choir for classical music of various periods and singer in a Schola Cantorum (Vokalschola), see "Links" section.
AuReLeE is funded by Luxembourg National Research Fund (FNR) under grant CORE C20/IS/14616644, proposer and PI (until end of 2022): A. Steen
The goal of the project Automated Reasoning with Legal Entities (AuReLeE) is to provide effective and general means for the automation of normative reasoning processes based on legal knowledge bases. To this end, the project will design and implement a dedicated system that combines efficient decision procedures with a flexible approach to import and re-use existing knowledge bases for their employment as underlying contexts for the normative reasoning tasks. The results of AuReLeE hence allow to full utilization of the existing legal knowledge bases’ potential for compliance checking.
AuReLeE is conducted at the Faculty of Science, Technology and Medicine of the University of Luxembourg. It is hosted by the Individual and Collective Reasoning (ICR) research group at the Depart of Computer Science.Further information
Leo-III was funded by DFG under grant BE 2501/11-1 (Leo-III), PI: C. Benzmüller
Leo-III is an effective ATP system for HOL with Henkin semantics and choice. It is implemented in Scala; its source code, and that of related projects, is publicly available under BSD-3 license on GitHub. The system accepts all common TPTP input syntax formats, including untyped clause normal form (CNF), untyped and typed first-order logic (FOF and TFF, respectively) and, as primary input format, monomorphic higher-order logic (THF). Additionally, as one of the first higher-order ATP systems, Leo-III upports reasoning in rank-1 polymorphic variants of the above logics (TF1 and TH1 syntax). The prover returns results according to the standardized TPTP SZS ontology and produces a verifiable TPTP-compatible proof certificate, if a proof is found.
Leo-III was identified as one of the most effective (in terms of number of solved problems) and most versatile (in terms of supported logical formalisms) theorem prover to date by the GRUNGE evaluation, see arXiv:1903.02539.
Conducted at Dahlem Center of Machine Learning and Robotics of Freie Universität Berlin, joint work with T. Gleißner
MET is a tool for embedding modal logic logic problems into classical higher-order logic represented in TPTP THF format. The input language allows the user to specify the semantics of the desired quantified modal logic and automatically computes the correspondig embedding.Further information
Conducted at the Individual and Collective Reasoning group of University of Luxembourg, joint work with T. Libal
NAI (for Normative AI) is a framework for normative reasoning. NAI features an annotation-based editor which abstracts over the underlining logical language. It also contains an easily accessible functionality for quality assurance and a transparent analysis of the created formalized document. NAI also supports an approach for assessing the correctness of formalizations via execution of behavioral tests using so-called queries. Lastly, it provides an interface for the creation of such queries and for checking their validity. The architecture of NAI is modular, which allows using different logics and reasoning engines. It also provides an web-based interface, which can be used by other tools in order to reason over the formalized legislation.
NAI is open-source, its source code is freely available at GitHub 3 under GPL-3.0 license. It was awarded with the LexisNexis Best Paper Award of Internationales Rechtsinformatik Symposium (IRIS 2020), in Salzburg, Austria, 2020.Further information
I completed the advanced training certificate for unversity teaching (Hochschuldidaktisches Lehrzertifikat) of Freie Universität Berlin (Support für die Lehre).
Only showing the latest six teaching activities. » show complete list
Interested in writing a bachelors or masters thesis in the context of automated theorem proving or related areas? Feel free to contact me via e-mail.