May 2021: The COST Action
European Research Network on Formal Proofs
(EuroProofNet), of which I have been a co-proposer
together with 23 colleagues from 23 countries,
has been accepted for implementation!
EuroProofNet aims at boosting the interoperability and usability of proof systems
across different reasoning systems and applications.
The project is expected to start in autumn 2021.
May 2021: I'm organizing a kick-off event of my recently started AuReLeE project, including invited talks by Prof. Adam Wyner (Swansea Univ.) and Prof. Leon van der Torre (Univ. of Luxembourg). Everybody is welcome to join, see aurelee.net/kickoff for more information.
May 2021: The Luxembourg National Research Fund (FNR) published a short feature on my research: Spotlight on Young Researchers: AI for ethical and legal debates. Thanks a lot for the interest!
April 2021: I'm happy to announce that the project proposal Höhere Ordnungen - performative Recherche zu Künstlicher Intelligenz of Benedikt Grubel and myself was accepted for funding by the Fond Darstellende Künste (federal Performing Arts Fund in Germany) within the #TakeCare programme. In this project, we will explore processes and notions of perception, knowledge representation and language that are common in Theater and AI.
March 2021: My article on extensional paramodulation in Leo-III (jww Christoph Benzmüller) was published in the Journal of Automated Reasoning. You can access the article on Springer Link.
February 2021: I was appointed an expert jury member for the selection of German AI talents (KI-Newcomer*innen 2021), an award hosted by the KI Camp project of the German BMBF and the Gesellschaft für Informatik. Looking forward to it!
February/March 2021: I will be giving a lecture for the general public on Knowledge Representation and Reasoning, as part of the Elements of AI MOOC and webinar series (Chapter 3, "Real world AI"). See also the UL announcement for further information.
February 2021: The special interest group Deduction Systems (Fachgruppe Deduktionssysteme) of the German GI (Gesellschaft für Informatik) is having a joint logic online workshop on March 26, 2021, including the annual Deduktionstreffen. All interested in logic/deduction are invited to contribute! See further information at the interest group website.
February 2021: I'm very happy to announce that David Fuenmayor agreed join my AuReLeE project as a team member. AuReLeE is expected to start in March 2021.
October 2020: I'm honored that my research project proposal AuReLeE (Automatead Reasoning With Legal Entities) has been approved for funding by the FNR within the CORE funding scheme (junior track), see also the official announcement of the FNR. Further information will follow soon.
June 18-20, 2021:
1st International Workshop on Logics for New-Generation Artificial Intelligence (LNGAI 2021), Hangzhou, China. (contributing speaker)
July 11-16, 2021: 28th International Conference on Automated Deduction (CADE-28), Pittsburgh, PA, USA. (Workshop and Tutorial Chair)
July 21-24, 2021: 15th International Conference on Deontic Logic and Normative Systems (DEON 2020/2021), Munich, Germany. (contributing speaker)
August 21-26, 2021: 30th International Joint Conference on Artificial Intelligence (IJCAI-21), Montreal, Canada. (PC member)
September 8-10, 2021: PhDs in Logic XII, Berlin, Germany. (Invited Speaker)
September 27-October 1, 2021: 44th German Conference on Artificial Intelligence (KI 2021), Berlin, Germany.
November, 2021: 33th Benelux Conference on Artificial Intelligence and the 30th Belgian Dutch Conference on Machine Learning, Esch/Alzette, Luxembourg.
This is the personal homepage of Alexander Steen. I am a post-doctoral researcher at the Faculty of Science, Technology and Medicine (FSTM) of the University of Luxembourg. I'm working on 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). 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.
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.