Journal Articles and Book Chapters

2022

• Stefan Borgwardt, Walter Forkel, and Alisa Kovtunova. Temporal minimal-world query answering over sparse ABoxes. Theory and Practice of Logic Programming, 22(2):192–228, March 2022.
  doi:10.1017/S1471068421000119

2020

• Franz Baader, Stefan Borgwardt, Patrick Koopmann, Veronika Thost, and Anni-Yasmin Turhan. Semantic technologies for situation awareness. KI - Künstliche Intelligenz, 34:543–550, November 2020. Project report.
  doi:10.1007/s13218-020-00694-3
• Franz Baader, Stefan Borgwardt, Patrick Koopmann, Ana Ozaki, and Veronika Thost. Metric temporal description logics with interval-rigid names. ACM Transactions on Computational Logic, 21(4):30:1–30:46, August 2020.
  doi:10.1145/3399443

2017

• Stefan Borgwardt, Marco Cerami, and Rafael Peñaloza. The complexity of fuzzy ${E}{L}$ under the Łukasiewicz t-norm. International Journal of Approximate Reasoning, 91:179–201, December 2017.
  doi:10.1016/j.ijar.2017.09.005
• Stefan Borgwardt and Rafael Peñaloza. Algorithms for reasoning in very expressive description logics under infinitely valued Gödel semantics. International Journal of Approximate Reasoning, 83:60–101, April 2017.
  doi:10.1016/j.ijar.2016.12.014
• Franz Baader, Stefan Borgwardt, and Rafael Peñaloza. Decidability and complexity of fuzzy description logics. KI - Künstliche Intelligenz, 31:85–90, March 2017. Project report.
  doi:10.1007/s13218-016-0459-3

2016

• Franz Baader, Nguyen Thanh Binh, Stefan Borgwardt, and Barbara Morawska. Deciding unifiability and computing local unifiers in the description logic ${E}{L}$ without top constructor. Notre Dame Journal of Formal Logic, 57(4):443–476, October 2016.
  doi:10.1215/00294527-3555507
• Franz Baader, Stefan Borgwardt, and Barbara Morawska. Extending unification in ${E}{L}$ to disunification: The case of dismatching and local disunification. Logical Methods in Computer Science, 12(4:1):1–28, October 2016.
  doi:10.2168/LMCS-12(4:1)2016
• Stefan Borgwardt and Rafael Peñaloza. Reasoning in fuzzy description logics using automata. Fuzzy Sets and Systems, 298:22–43, September 2016.
  doi:10.1016/j.fss.2015.07.013
• Stefan Borgwardt, Theofilos Mailis, Rafael Peñaloza, and Anni-Yasmin Turhan. Answering fuzzy conjunctive queries over finitely valued fuzzy ontologies. Journal on Data Semantics, 5(2):55–75, June 2016.
  doi:10.1007/s13740-015-0055-y

2015

• Franz Baader, Stefan Borgwardt, and Marcel Lippmann. Temporal query entailment in the description logic ${S}{H}{Q}$. Journal of Web Semantics, 33:71–93, August 2015.
  doi:10.1016/j.websem.2014.11.008
• Stefan Borgwardt, Marcel Lippmann, and Veronika Thost. Temporalizing rewritable query languages over knowledge bases. Journal of Web Semantics, 33:50–70, August 2015.
  doi:10.1016/j.websem.2014.11.007
• Franz Baader, Stefan Borgwardt, and Rafael Peñaloza. On the decidability status of fuzzy ${A}{L}{C}$ with general concept inclusions. Journal of Philosophical Logic, 44(2):117–146, April 2015.
  doi:10.1007/s10992-014-9329-3
• Stefan Borgwardt, Felix Distel, and Rafael Peñaloza. The limits of decidability in fuzzy description logics with general concept inclusions. Artificial Intelligence, 218:23–55, January 2015.
  doi:10.1016/j.artint.2014.09.001

2014

• Stefan Borgwardt and Rafael Peñaloza. Consistency reasoning in lattice-based fuzzy description logics. International Journal of Approximate Reasoning, 55(9):1917–1938, December 2014.
  doi:10.1016/j.ijar.2013.07.006
• Stefan Borgwardt and Rafael Peñaloza. Finite lattices do not make reasoning in ${A}{L}{C}{O}{I}$ harder. In Fernando Bobillo, Rommel N. Carvalho, Paulo C. G. da Costa, Claudia d’Amato, Nicola Fanizzi, Kathryn B. Laskey, Kenneth J. Laskey, Thomas Lukasiewicz, Matthias Nickles, and Mike Pool, editors, Uncertainty Reasoning for the Semantic Web III, volume 8816 of Lecture Notes in Artificial Intelligence, pages 122–141. Springer-Verlag, November 2014.
  doi:10.1007/978-3-319-13413-0_7

2013

• Stefan Borgwardt and Rafael Peñaloza. The complexity of lattice-based fuzzy description logics. Journal on Data Semantics, 2(1):1–19, March 2013.
  doi:10.1007/s13740-012-0013-x

Peer-Reviewed Conference Publications

2024

• Christian Alrabbaa, Stefan Borgwardt, Tom Friese, Anke Hirsch, Nina Knieriemen, Patrick Koopmann, Alisa Kovtunova, Antonio Krüger, Alexej Popovič, and Ida Siahaan. Explaining reasoning results for OWL ontologies with Evee. In Pierre Marquis, Magdalena Ortiz, and Maurice Pagnucco, editors, 21st International Conference on Knowledge Representation and Reasoning (KR’24), pages 709–719, Hanoi, Vietnam, November 2, 2024. IJCAI. KR in the Wild track.
  doi:10.24963/kr.2024/67

2023

• Christian Alrabbaa, Franz Baader, Stefan Borgwardt, Patrick Koopmann, and Alisa Kovtunova. Combining proofs for description logic and concrete domain reasoning. In Anna Fensel and Ana Ozaki, editors, Proceedings of the 7th International Joint Conference on Rules and Reasoning (RuleML+RR’23), volume 14244 of Lecture Notes in Computer Science, pages 54–69, Oslo, Norway, September 18, 2023. Springer-Verlag. Harold Boley Distinguished Paper Award.
  doi:10.1007/978-3-031-45072-3_4
  Extended version: https://arxiv.org/abs/2308.03705

2022

• Christian Alrabbaa, Stefan Borgwardt, Anke Hirsch, Nina Knieriemen, Alisa Kovtunova, Anna Milena Rothermel, and Frederik Wiehr. In the head of the beholder: Comparing different proof representations. In Guido Governatori and Anni-Yasmin Turhan, editors, Proceedings of the 6th International Joint Conference on Rules and Reasoning (RuleML+RR’22), volume 13752 of Lecture Notes in Computer Science, pages 211–226, Online [Berlin, Germany], September 26, 2022. Springer-Verlag. Best Paper Award.
  doi:10.1007/978-3-031-21541-4_14
• Christian Alrabbaa, Stefan Borgwardt, Patrick Koopmann, and Alisa Kovtunova. Explaining ontology-mediated query answers using proofs over universal models. In Guido Governatori and Anni-Yasmin Turhan, editors, Proceedings of the 6th International Joint Conference on Rules and Reasoning (RuleML+RR’22), volume 13752 of Lecture Notes in Computer Science, pages 167–182, Online [Berlin, Germany], September 26, 2022. Springer-Verlag.
  doi:10.1007/978-3-031-21541-4_11
  Extended version: https://arxiv.org/abs/2208.14381
• Christian Alrabbaa, Franz Baader, Stefan Borgwardt, Raimund Dachselt, Patrick Koopmann, and Julián Méndez. Evonne: Interactive proof visualization for description logics (System description). In Jasmin Blanchette, Laura Kovács, and Dirk Pattinson, editors, Proceedings of the 11th International Joint Conference on Automated Reasoning (IJCAR’22), volume 13385 of Lecture Notes in Computer Science, pages 271–280, Haifa, Israel, August 8, 2022. Springer-Verlag.
  doi:10.1007/978-3-031-10769-6_16
  Extended version: https://arxiv.org/abs/2205.09583
• Ernie Chang, Alisa Kovtunova, Stefan Borgwardt, Vera Demberg, Kathryn Chapman, and Hui-Syuan Yeh. Logic-guided message generation from raw real-time sensor data. In Nicoletta Calzolari, Frédéric Béchet, Philippe Blache, Khalid Choukri, Christopher Cieri, Thierry Declerck, Sara Goggi, Hitoshi Isahara, Bente Maegaard, Joseph Mariani, Hélène Mazo, Jan Odijk, and Stelios Piperidis, editors, Proceedings of the 13th Language Resources and Evaluation Conference (LREC’22), pages 6899–6908, Marseille, France, June 21, 2022. European Language Resources Association.
  http://www.lrec-conf.org/proceedings/lrec2022/pdf/2022.lrec-1.745.pdf
• Stefan Borgwardt, Jörg Hoffmann, Alisa Kovtunova, Markus Krötzsch, Bernhard Nebel, and Marcel Steinmetz. Expressivity of planning with Horn description logic ontologies. In Katia Sycara, Vasant Honavar, and Matthijs Spaan, editors, Proceedings of the 36th AAAI Conference on Artificial Intelligence (AAAI’22), pages 5503–5511, Online [Vancouver, Canada], February 22, 2022. AAAI Press.
  doi:10.1609/aaai.v36i5.20489
• Marcel Steinmetz, Jörg Hoffmann, Alisa Kovtunova, and Stefan Borgwardt. Classical planning with avoid conditions. In Katia Sycara, Vasant Honavar, and Matthijs Spaan, editors, Proceedings of the 36th AAAI Conference on Artificial Intelligence (AAAI’22), pages 9944–9952, Online [Vancouver, Canada], February 22, 2022. AAAI Press.
  doi:10.1609/aaai.v36i9.21232
  Extended version: https://fai.cs.uni-saarland.de/steinmetz/aaai22_tr.pdf

2021

• Stefan Borgwardt, Jörg Hoffmann, Alisa Kovtunova, and Marcel Steinmetz. Making DL-Lite planning practical. In Meghyn Bienvenu and Gerhard Lakemeyer, editors, Proceedings of the 18th International Conference on Principles of Knowledge Representation and Reasoning (KR’21), pages 641–645, Online [Hanoi, Vietnam], November 8, 2021. IJCAI. Short paper.
  doi:10.24963/kr.2021/61
• Frederik Wiehr, Anke Hirsch, Lukas Schmitz, Nina Knieriemen, Alisa Kovtunova, Stefan Borgwardt, Ernie Chang, Vera Demberg, Marcel Steinmetz, Jörg Hoffmann, and Antonio Krüger. Why do I have to take over control? Evaluating safe handovers with advance notice and explanations in highly automated driving. In Sharon Oviatt, Albert Ali Salah, and Guoying Zhao, editors, Proceedings of the 23rd ACM International Conference on Multimodal Interaction (ICMI’21), pages 308–317, Montreal, Canada, October 18, 2021. ACM.
  doi:10.1145/3462244.3479884
• Christian Alrabbaa, Franz Baader, Stefan Borgwardt, Patrick Koopmann, and Alisa Kovtunova. Finding good proofs for description logic entailments using recursive quality measures. In André Platzer and Geoff Sutcliffe, editors, Proceedings of the 28th International Conference on Automated Deduction (CADE’21), volume 12699 of Lecture Notes in Computer Science, pages 291–308, Online, July 12, 2021. Springer-Verlag.
  doi:10.1007/978-3-030-79876-5_17
  Extended version: https://arxiv.org/abs/2104.13138

2020

• Christian Alrabbaa, Franz Baader, Stefan Borgwardt, Patrick Koopmann, and Alisa Kovtunova. Finding small proofs for description logic entailments: Theory and practice. In Elvira Albert and Laura Kovács, editors, Proceedings of the 23rd International Conference on Logic for Programming, Artificial Intelligence and Reasoning (LPAR’20), volume 73 of EasyChair Proceedings in Computing, pages 32–67, Online, May 22, 2020. EasyChair.
  doi:10.29007/nhpp

2019

• Stefan Borgwardt, Walter Forkel, and Alisa Kovtunova. Finding new diamonds: Temporal minimal-world query answering over sparse ABoxes. In Paul Foder, Marco Montali, Diego Calvanese, and Dumitru Roman, editors, Proceedings of the 3rd International Joint Conference on Rules and Reasoning (RuleML+RR’19), volume 11784 of Lecture Notes in Computer Science, pages 3–18, Bolzano, Italy, September 16, 2019. Springer-Verlag.
  doi:10.1007/978-3-030-31095-0_1
  Extended version: doi:10.1017/S1471068421000119
• Stefan Borgwardt and Walter Forkel. Closed-world semantics for conjunctive queries with negation over ${{E}{L}{H}}_{\perp }$ ontologies. In Sarit Kraus, editor, Proceedings of the 28th International Joint Conference on Artificial Intelligence (IJCAI’19), pages 6131–6135, Macao, China, August 10, 2019. IJCAI. Invited contribution to Sister Conference Best Paper Track.
  doi:10.24963/ijcai.2019/849
  Extended version: doi:10.1017/S1471068421000119
• Stefan Borgwardt and Walter Forkel. Closed-world semantics for conjunctive queries with negation over ${{E}{L}{H}}_{\perp }$ ontologies. In Francesco Calimeri, Nicola Leone, and Marco Manna, editors, Proceedings of the 16th European Conference on Logics in Artificial Intelligence (JELIA’19), volume 11468 of Lecture Notes in Artificial Intelligence, pages 371–386, Rende, Italy, May 7, 2019. Springer-Verlag. Best Paper Award.
  doi:10.1007/978-3-030-19570-0_24
  Extended version: doi:10.1017/S1471068421000119
• Stefan Borgwardt, İsmail İlkan Ceylan, and Thomas Lukasiewicz. Ontology-mediated query answering over log-linear probabilistic data. In Pascal Van Hentenryck and Zhi-Hua Zhou, editors, Proceedings of the 33rd AAAI Conference on Artificial Intelligence (AAAI’19), pages 2711–2718, Honolulu, USA, January 27, 2019. AAAI Press.
  doi:10.1609/aaai.v33i01.33012711
  Extended version: https://lat.inf.tu-dresden.de/research/reports.html#latpub:BoCL-LTCS-19-10

2018

• Stefan Borgwardt, İsmail İlkan Ceylan, and Thomas Lukasiewicz. Recent advances in querying probabilistic knowledge bases. In Jérôme Lang, editor, Proceedings of the 27th International Joint Conference on Artificial Intelligence and the 23rd European Conference on Artificial Intelligence (IJCAI-ECAI’18), pages 5420–5426, Stockholm, Sweden, July 13, 2018. IJCAI. Survey paper.
  doi:10.24963/ijcai.2018/765

2017

• Stefan Borgwardt and Rafael Peñaloza. Fuzzy description logics – A survey. In Serafín Moral, Olivier Pivert, Daniel Sánchez, and Nicolás Marín, editors, Proceedings of the 11th International Conference on Scalable Uncertainty Management (SUM’17), volume 10564 of Lecture Notes in Computer Science, pages 31–45, Granada, Spain, October 4, 2017. Springer-Verlag. Invited paper.
  doi:10.1007/978-3-319-67582-4_3
• Franz Baader, Stefan Borgwardt, Patrick Koopmann, Ana Ozaki, and Veronika Thost. Metric temporal description logics with interval-rigid names. In Clare Dixon and Marcelo Finger, editors, Proceedings of the 11th International Symposium on Frontiers of Combining Systems (FroCoS’17), volume 10483 of Lecture Notes in Computer Science, pages 60–76, Brasília, Brazil, September 27, 2017. Springer-Verlag.
  doi:10.1007/978-3-319-66167-4_4
  Extended version: doi:10.1145/3399443
• Franz Baader, Stefan Borgwardt, and Marcel Lippmann. Query rewriting for DL-Lite with $n$-ary concrete domains. In Carles Sierra, editor, Proceedings of the 26th International Joint Conference on Artificial Intelligence (IJCAI’17), pages 786–792, Melbourne, Australia, August 19, 2017. IJCAI.
  doi:10.24963/ijcai.2017/109
  Extended version: doi:10.25368/2022.234
• İsmail İlkan Ceylan, Stefan Borgwardt, and Thomas Lukasiewicz. Most probable explanations for probabilistic database queries. In Carles Sierra, editor, Proceedings of the 26th International Joint Conference on Artificial Intelligence (IJCAI’17), pages 950–956, Melbourne, Australia, August 19, 2017. IJCAI.
  doi:10.24963/ijcai.2017/132
  Extended version: https://lat.inf.tu-dresden.de/research/reports.html#latpub:CeBL-LTCS-17-11
• Stefan Borgwardt, İsmail İlkan Ceylan, and Thomas Lukasiewicz. Ontology-mediated queries for probabilistic databases. In Satinder Singh and Shaul Markovitch, editors, Proceedings of the 31st AAAI Conference on Artificial Intelligence (AAAI’17), pages 1063–1069, San Francisco, USA, February 6, 2017. AAAI Press.
  doi:10.1609/aaai.v31i1.10680
  Extended version: https://lat.inf.tu-dresden.de/research/reports.html#latpub:BoCL-LTCS-17-10

2016

• Stefan Borgwardt, Bettina Fazzinga, Thomas Lukasiewicz, Akanksha Shrivastava, and Oana Tifrea-Marciuska. Preferential query answering in the Semantic Web with possibilistic networks. In Subbarao Kambhampati, editor, Proceedings of the 25th International Joint Conference on Artificial Intelligence (IJCAI’16), pages 994–1000, New York City, USA, July 12, 2016. AAAI Press.
  https://ijcai.org/Abstract/16/145
  Extended version: https://lat.inf.tu-dresden.de/research/reports.html#latpub:BFLST-LTCS-16-10

2015

• Franz Baader, Stefan Borgwardt, and Marcel Lippmann. Temporal conjunctive queries in expressive description logics with transitive roles. In Bernhard Pfahringer and Jochen Renz, editors, Proceedings of the 28th Australasian Joint Conference on Artificial Intelligence (AI’15), volume 9457 of Lecture Notes in Artificial Intelligence, pages 21–33, Canberra, Australia, November 30, 2015. Springer-Verlag. Best Paper Award.
  doi:10.1007/978-3-319-26350-2_3
  Extended version: doi:10.25368/2022.222
• Stefan Borgwardt and Veronika Thost. Temporal query answering in DL-Lite with negation. In Georg Gottlob, Geoff Sutcliffe, and Andrei Voronkov, editors, Proceedings of the 1st Global Conference on Artificial Intelligence (GCAI’15), volume 36 of EasyChair Proceedings in Computing, pages 51–65, Tblisi, Georgia, October 16, 2015. EasyChair.
  doi:10.29007/2df8
  Extended version: doi:10.25368/2022.221
• Stefan Borgwardt and Rafael Peñaloza. Reasoning in expressive description logics under infinitely valued Gödel semantics. In Carsten Lutz and Silvio Ranise, editors, Proceedings of the 10th International Symposium on Frontiers of Combining Systems (FroCoS’15), volume 9322 of Lecture Notes in Artificial Intelligence, pages 49–65, Wrocław, Poland, September 19, 2015. Springer-Verlag.
  doi:10.1007/978-3-319-24246-0_4
  Extended version: doi:10.1016/j.ijar.2016.12.014
• Stefan Borgwardt, Marco Cerami, and Rafael Peñaloza. The complexity of subsumption in fuzzy ${E}{L}$. In Qiang Yang and Michael Wooldridge, editors, Proceedings of the 24th International Joint Conference on Artificial Intelligence (IJCAI’15), pages 2812–2818, Buenos Aires, Argentina, July 25, 2015. AAAI Press. Short presentation.
  https://ijcai.org/Abstract/15/398
  Extended version: doi:10.1016/j.ijar.2017.09.005
• Stefan Borgwardt and Veronika Thost. Temporal query answering in the description logic ${E}{L}$. In Qiang Yang and Michael Wooldridge, editors, Proceedings of the 24th International Joint Conference on Artificial Intelligence (IJCAI’15), pages 2819–2825, Buenos Aires, Argentina, July 25, 2015. AAAI Press.
  https://ijcai.org/Abstract/15/399
  Extended version: doi:10.25368/2022.214
• Franz Baader, Stefan Borgwardt, and Barbara Morawska. Dismatching and local disunification in ${E}{L}$. In Maribel Fernández, editor, Proceedings of the 26th International Conference on Rewriting Techniques and Applications (RTA’15), volume 36 of Leibniz International Proceedings in Informatics, pages 40–56, Warsaw, Poland, June 29, 2015. Dagstuhl Publishing.
  doi:10.4230/LIPIcs.RTA.2015.40
  Extended version: doi:10.2168/LMCS-12(4:1)2016

2014

• Stefan Borgwardt, José A. Leyva Galano, and Rafael Peñaloza. The fuzzy description logic $G\text{-}{{F}{L}}_0$ with greatest fixed-point semantics. In Eduardo Fermé and João Leite, editors, Proceedings of the 14th European Conference on Logics in Artificial Intelligence (JELIA’14), volume 8761 of Lecture Notes in Artificial Intelligence, pages 62–76, Funchal, Portugal, September 24, 2014. Springer-Verlag.
  doi:10.1007/978-3-319-11558-0_5
• Stefan Borgwardt, Felix Distel, and Rafael Peñaloza. Decidable Gödel description logics without the finitely-valued model property. In Chitta Baral, Giuseppe De Giacomo, and Thomas Eiter, editors, Proceedings of the 14th International Conference on Principles of Knowledge Representation and Reasoning (KR’14), pages 228–237, Vienna, Austria, July 20, 2014. AAAI Press.
  https://aaai.org/papers/0228-7803-decidable-godel-description-logics-without-the-finitely-valued-model-property/
  Extended version: doi:10.25368/2022.199

2013

• Stefan Borgwardt, Marcel Lippmann, and Veronika Thost. Temporal query answering in the description logic DL-Lite. In Pascal Fontaine, Christophe Ringeissen, and Renate A. Schmidt, editors, Proceedings of the 9th International Symposium on Frontiers of Combining Systems (FroCoS’13), volume 8152 of Lecture Notes in Artificial Intelligence, pages 165–180, Nancy, France, September 18, 2013. Springer-Verlag.
  doi:10.1007/978-3-642-40885-4_11
  Extended version: doi:10.1016/j.websem.2014.11.007
• Stefan Borgwardt and Rafael Peñaloza. Positive subsumption in fuzzy ${E}{L}$ with general t-norms. In Francesca Rossi, editor, Proceedings of the 23rd International Joint Conference on Artificial Intelligence (IJCAI’13), pages 789–795, Beijing, China, August 3, 2013. AAAI Press.
  https://ijcai.org/Abstract/13/123
• Franz Baader, Stefan Borgwardt, and Marcel Lippmann. Temporalizing ontology-based data access. In Maria Paola Bonacina, editor, Proceedings of the 24th International Conference on Automated Deduction (CADE’13), volume 7898 of Lecture Notes in Artificial Intelligence, pages 330–344, Lake Placid, NY, USA, June 9, 2013. Springer-Verlag.
  doi:10.1007/978-3-642-38574-2_23
  Extended version: doi:10.1016/j.websem.2014.11.008

2012

• Franz Baader, Stefan Borgwardt, and Barbara Morawska. A goal-oriented algorithm for unification in ${{E}{L}{H}}_{R^{+}}$ w.r.t. cycle-restricted ontologies. In Michael Thielscher and Dongmo Zhang, editors, Proceedings of the 25th Australasian Joint Conference on Artificial Intelligence (AI’12), volume 7691 of Lecture Notes in Artificial Intelligence, pages 493–504, Sydney, Australia, December 4, 2012. Springer-Verlag.
  doi:10.1007/978-3-642-35101-3_42
  Extended version: doi:10.25368/2022.189
• Stefan Borgwardt and Rafael Peñaloza. A tableau algorithm for fuzzy description logics over residuated De Morgan lattices. In Markus Krötzsch and Umberto Straccia, editors, Proceedings of the 6th International Conference on Web Reasoning and Rule Systems (RR’12), volume 7497 of Lecture Notes in Computer Science, pages 9–24, Vienna, Austria, September 10, 2012. Springer-Verlag. Runner-up for Best Paper Award.
  doi:10.1007/978-3-642-33203-6_3
  Extended version: doi:10.1016/j.ijar.2013.07.006
• Franz Baader, Stefan Borgwardt, and Barbara Morawska. Computing minimal ${E}{L}$-unifiers is hard. In Thomas Bolander, Torben Braüner, Silvio Ghilardi, and Lawrence Moss, editors, Advances in Modal Logic 9 (AiML’12), pages 18–35, Copenhagen, Denmark, August 22, 2012. College Publications.
  http://www.aiml.net/volumes/volume9/Baader-Borgwardt-Morawska.pdf
  Extended version: doi:10.25368/2022.187
• Franz Baader, Stefan Borgwardt, and Barbara Morawska. SAT-encoding of unification in ${{E}{L}{H}}_{R^{+}}$ w.r.t. cycle-restricted ontologies. In Bernhard Gramlich, Dale Miller, and Uli Sattler, editors, Proceedings of the 6th International Joint Conference on Automated Reasoning (IJCAR’12), volume 7364 of Lecture Notes in Artificial Intelligence, pages 30–44, Manchester, UK, June 26, 2012. Springer-Verlag.
  doi:10.1007/978-3-642-31365-3_5
  Extended version: doi:10.25368/2022.186
• Stefan Borgwardt, Felix Distel, and Rafael Peñaloza. How fuzzy is my fuzzy description logic? In Bernhard Gramlich, Dale Miller, and Uli Sattler, editors, Proceedings of the 6th International Joint Conference on Automated Reasoning (IJCAR’12), volume 7364 of Lecture Notes in Artificial Intelligence, pages 82–96, Manchester, UK, June 26, 2012. Springer-Verlag.
  doi:10.1007/978-3-642-31365-3_9
  Extended version: doi:10.1016/j.artint.2014.09.001
• Franz Baader, Stefan Borgwardt, and Barbara Morawska. Extending unification in ${E}{L}$ towards general TBoxes. In Gerhard Brewka, Thomas Eiter, and Sheila A. McIlraith, editors, Proceedings of the 13th International Conference on Principles of Knowledge Representation and Reasoning (KR’12), pages 568–572, Rome, Italy, June 10, 2012. AAAI Press. Short paper.
  https://aaai.org/papers/61-4491-extending-unification-in-el-towards-general-tboxes/
  Extended version: doi:10.25368/2022.183
• Stefan Borgwardt and Rafael Peñaloza. Undecidability of fuzzy description logics. In Gerhard Brewka, Thomas Eiter, and Sheila A. McIlraith, editors, Proceedings of the 13th International Conference on Principles of Knowledge Representation and Reasoning (KR’12), pages 232–242, Rome, Italy, June 10, 2012. AAAI Press.
  https://aaai.org/papers/29-4387-undecidability-of-fuzzy-description-logics/
  Extended version: doi:10.1016/j.artint.2014.09.001
• Stefan Borgwardt and Barbara Morawska. Finding finite Herbrand models. In Nikolaj Bjørner and Andrei Voronkov, editors, Proceedings of the 18th International Conference on Logic for Programming, Artificial Intelligence, and Reasoning (LPAR’12), volume 7180 of Lecture Notes in Computer Science, pages 138–152, Mérida, Venezuela, March 11, 2012. Springer-Verlag.
  doi:10.1007/978-3-642-28717-6_13
  Extended version: doi:10.25368/2022.182

2011

• Stefan Borgwardt and Rafael Peñaloza. The inclusion problem for weighted automata on infinite trees. In Pál Dömösi and Szabolcs Iván, editors, Proceedings of the 13th International Conference on Automata and Formal Languages (AFL’11), pages 108–122, Debrecen, Hungary, August 17, 2011. College of Nyíregyháza.
  ISBN 978-615-5097-19-5
  Extended version: doi:10.25368/2022.180
• Franz Baader, Nguyen Thanh Binh, Stefan Borgwardt, and Barbara Morawska. Unification in the description logic ${E}{L}$ without the top concept. In Nikolaj Bjørner and Viorica Sofronie-Stokkermans, editors, Proceedings of the 23rd International Conference on Automated Deduction (CADE’11), volume 6803 of Lecture Notes in Artificial Intelligence, pages 70–84, Wrocław, Poland, August 2, 2011. Springer-Verlag.
  doi:10.1007/978-3-642-22438-6_8
  Extended version: doi:10.1215/00294527-3555507
• Stefan Borgwardt and Rafael Peñaloza. Description logics over lattices with multi-valued ontologies. In Toby Walsh, editor, Proceedings of the 22nd International Joint Conference on Artificial Intelligence (IJCAI’11), pages 768–773, Barcelona, Spain, July 16, 2011. AAAI Press.
  doi:10.5591/978-1-57735-516-8/IJCAI11-135
  Extended version: doi:10.1007/s13740-012-0013-x

Workshop, Video, and Other Publications

2024

• Christian Alrabbaa, Stefan Borgwardt, Tom Friese, Anke Hirsch, Nina Knieriemen, Patrick Koopmann, Alisa Kovtunova, Antonio Krüger, Alexej Popovič, and Ida Siahaan. Explaining reasoning results for OWL ontologies with Evee (Extended abstract). In Nico Potyka, editor, Proceedings of the 5th Workshop on Explainable Logic-Based Knowledge Representation (XLoKR’24), Hanoi, Vietnam, November 2, 2024.
  https://sites.google.com/view/xlokr2024
  Extended version: doi:10.24963/kr.2024/67
• Christian Alrabbaa, Stefan Borgwardt, Tom Friese, Patrick Koopmann, Alisa Kovtunova, and Ida Siahaan. Explaining description logic reasoning slice by slice with Evee. In Nico Potyka and Anni-Yasmin Turhan, editors, Video Track of the 21st International Conference on Knowledge Representation and Reasoning (KR’24), Hanoi, Vietnam, November 2, 2024. YouTube.
  https://youtu.be/DUDWp2YmhaY
• Stefan Borgwardt, Vera Demberg, Mayank Jobanputra, Alisa Kovtunova, and Duy Nhu. Explaining critical situations over sensor data streams using proofs and natural language (Extended abstract). In Nico Potyka, editor, Proceedings of the 5th Workshop on Explainable Logic-Based Knowledge Representation (XLoKR’24), Hanoi, Vietnam, November 2, 2024.
  https://sites.google.com/view/xlokr2024
  Extended version: https://ceur-ws.org/Vol-3739/paper-2.pdf
• Stefan Borgwardt, Filippo De Bortoli, and Patrick Koopmann. The precise complexity of reasoning in ${A}{L}{C}$ with $\omega$-admissible concrete domains. In Jean Christoph Jung, Laura Giordano, and Ana Ozaki, editors, Proceedings of the 37th International Workshop on Description Logics (DL’24), volume 3739 of CEUR Workshop Proceedings, Bergen, Norway, June 18, 2024.
  https://ceur-ws.org/Vol-3739/paper-1.pdf
• Stefan Borgwardt, Vera Demberg, Mayank Jobanputra, Alisa Kovtunova, and Duy Nhu. Explaining critical situations over sensor data streams using proofs and natural language. In Jean Christoph Jung, Laura Giordano, and Ana Ozaki, editors, Proceedings of the 37th International Workshop on Description Logics (DL’24), volume 3739 of CEUR Workshop Proceedings, Bergen, Norway, June 18, 2024. Best Student Contribution Award.
  https://ceur-ws.org/Vol-3739/paper-2.pdf

2023

• Christian Alrabbaa, Franz Baader, Stefan Borgwardt, Patrick Koopmann, and Alisa Kovtunova. Combining proofs for description logic and concrete domain reasoning (Extended abstract). In Nico Potyka, editor, Proceedings of the 4th Workshop on Explainable Logic-Based Knowledge Representation (XLoKR’23), Rhodes, Greece, September 2, 2023.
  https://sites.google.com/view/xlokr2023
  Extended version: doi:10.1007/978-3-031-45072-3_4
• Christian Alrabbaa, Stefan Borgwardt, Tom Friese, Patrick Koopmann, and Mikhail Kotlov. Why not? Explaining missing entailments with Evee. In Oliver Kutz, Carsten Lutz, and Ana Ozaki, editors, Proceedings of the 36th International Workshop on Description Logics (DL’23), volume 3513 of CEUR Workshop Proceedings, Rhodes, Greece, September 2, 2023.
  https://ceur-ws.org/Vol-3515/paper-1.pdf
  Extended version: https://arxiv.org/abs/2308.07294
• Stefan Borgwardt, Steffen Breuer, and Alisa Kovtunova. Computing ABox justifications for query answers via Datalog rewriting. In Oliver Kutz, Carsten Lutz, and Ana Ozaki, editors, Proceedings of the 36th International Workshop on Description Logics (DL’23), volume 3513 of CEUR Workshop Proceedings, Rhodes, Greece, September 2, 2023.
  https://ceur-ws.org/Vol-3515/paper-8.pdf

2022

• Christian Alrabbaa, Stefan Borgwardt, Tom Friese, Patrick Koopmann, Julián Méndez, and Alexej Popovič. On the eve of true explainability for OWL ontologies: Description logic proofs with Evee and Evonne. In Ofer Arieli, Martin Homola, Jean Christoph Jung, and Marie-Laure Mugnier, editors, Proceedings of the 35th International Workshop on Description Logics (DL’22), volume 3263 of CEUR Workshop Proceedings, Haifa, Israel, August 7, 2022.
  https://ceur-ws.org/Vol-3263/paper-2.pdf
  Extended version: https://arxiv.org/abs/2206.07711
• Christian Alrabbaa, Stefan Borgwardt, Patrick Koopmann, and Alisa Kovtunova. Finding good proofs for answers to conjunctive queries mediated by lightweight ontologies. In Ofer Arieli, Martin Homola, Jean Christoph Jung, and Marie-Laure Mugnier, editors, Proceedings of the 35th International Workshop on Description Logics (DL’22), volume 3263 of CEUR Workshop Proceedings, Haifa, Israel, August 7, 2022.
  https://ceur-ws.org/Vol-3263/paper-3.pdf
  Extended version: doi:10.1007/978-3-031-21541-4_11
• Stefan Borgwardt, Jörg Hoffmann, Alisa Kovtunova, Markus Krötzsch, Bernhard Nebel, and Marcel Steinmetz. Expressivity of planning with Horn description logic ontologies (extended abstract). In Ofer Arieli, Martin Homola, Jean Christoph Jung, and Marie-Laure Mugnier, editors, Proceedings of the 35th International Workshop on Description Logics (DL’22), volume 3263 of CEUR Workshop Proceedings, Haifa, Israel, August 7, 2022.
  https://ceur-ws.org/Vol-3263/abstract-5.pdf
  Extended version: doi:10.1609/aaai.v36i5.20489
• Christian Alrabbaa, Stefan Borgwardt, Tom Friese, Patrick Koopmann, Julián Méndez, and Alexej Popovič. Explaining description logic entailments in practice with Evee and Evonne. In Nico Potyka, editor, 3rd Workshop on Explainable Logic-Based Knowledge Representation (XLoKR’22), Haifa, Israel, July 31, 2022.
  https://sites.google.com/view/xlokr2022
  Extended version: https://ceur-ws.org/Vol-3263/paper-2.pdf
• Christian Alrabbaa, Stefan Borgwardt, Patrick Koopmann, and Alisa Kovtunova. Finding good proofs for answers to conjunctive queries mediated by lightweight ontologies (extended abstract). In Nico Potyka, editor, 3rd Workshop on Explainable Logic-Based Knowledge Representation (XLoKR’22), Haifa, Israel, July 31, 2022.
  https://sites.google.com/view/xlokr2022
  Extended version: doi:10.1007/978-3-031-21541-4_11

2021

• Christian Alrabbaa, Stefan Borgwardt, Nina Knieriemen, Alisa Kovtunova, Anna Milena Rothermel, and Frederik Wiehr. In the hand of the beholder: Comparing interactive proof visualizations (extended abstract). In Bart Bogaerts, editor, 2nd Workshop on Explainable Logic-Based Knowledge Representation (XLoKR’21), Online [Hanoi, Vietnam], November 4, 2021.
  https://xlokr21.ai.vub.ac.be/papers/09/paper.pdf
  Extended version: doi:10.1007/978-3-031-21541-4_14
• Stefan Borgwardt. Concise justifications versus detailed proofs for description logic entailments. In Bart Bogaerts, editor, 2nd Workshop on Explainable Logic-Based Knowledge Representation (XLoKR’21), Online [Hanoi, Vietnam], November 4, 2021.
  https://xlokr21.ai.vub.ac.be/papers/04/paper.pdf
• Christian Alrabbaa, Franz Baader, Stefan Borgwardt, Patrick Koopmann, and Alisa Kovtunova. Finding good proofs for description logic entailments using recursive quality measures (extended abstract). In Martin Homola, Vladislav Ryzhikov, and Renate Schmidt, editors, Proceedings of the 34th International Workshop on Description Logics (DL’21), volume 2954 of CEUR Workshop Proceedings, Bratislava, Slovakia, September 19, 2021.
  https://ceur-ws.org/Vol-2954/abstract-2.pdf
  Extended version: doi:10.1007/978-3-030-79876-5_17
• Christian Alrabbaa, Stefan Borgwardt, Nina Knieriemen, Alisa Kovtunova, Anna Milena Rothermel, and Frederik Wiehr. In the hand of the beholder: Comparing interactive proof visualizations. In Martin Homola, Vladislav Ryzhikov, and Renate Schmidt, editors, Proceedings of the 34th International Workshop on Description Logics (DL’21), volume 2954 of CEUR Workshop Proceedings, Bratislava, Slovakia, September 19, 2021.
  https://ceur-ws.org/Vol-2954/paper-2.pdf
  Extended version: doi:10.1007/978-3-031-21541-4_14
• Stefan Borgwardt, Ernie Chang, Kathryn Chapman, Vera Demberg, Alisa Kovtunova, and Hui-Syuan Yeh. Logic-guided neural utterance generation from drone sensory data (extended abstract). In Martin Homola, Vladislav Ryzhikov, and Renate Schmidt, editors, Proceedings of the 34th International Workshop on Description Logics (DL’21), volume 2954 of CEUR Workshop Proceedings, Bratislava, Slovakia, September 19, 2021.
  https://ceur-ws.org/Vol-2954/abstract-11.pdf
  Extended version: http://www.lrec-conf.org/proceedings/lrec2022/pdf/2022.lrec-1.745.pdf
• Stefan Borgwardt, Jörg Hoffmann, Alisa Kovtunova, and Marcel Steinmetz. Making DL-Lite planning practical (extended abstract). In Martin Homola, Vladislav Ryzhikov, and Renate Schmidt, editors, Proceedings of the 34th International Workshop on Description Logics (DL’21), volume 2954 of CEUR Workshop Proceedings, Bratislava, Slovakia, September 19, 2021.
  https://ceur-ws.org/Vol-2954/abstract-7.pdf
  Extended version: doi:10.24963/kr.2021/61
• Stefan Borgwardt, Jörg Hoffmann, Alisa Kovtunova, and Marcel Steinmetz. Classical planning with avoid conditions. In Proceedings of the 13th Workshop on Heuristics and Search for Domain-Independent Planning (HSDIP’21), Online [Guangzhou, China], August 2, 2021.
  https://openreview.net/forum?id=-I8lSfnXFPI
  Extended version: doi:10.1609/aaai.v36i9.21232

2020

• Christian Alrabbaa, Stefan Borgwardt, Patrick Koopmann, and Alisa Kovtunova. Finding proofs for description logic entailments in practice (extended abstract). In Franz Baader, editor, Workshop on Explainable Logic-Based Knowledge Representation (XLoKR’20), Online [Rhodes, Greece], September 13, 2020.
  https://lat.inf.tu-dresden.de/XLoKR20/XLoKRpaper394.pdf
  Extended version: doi:10.29007/nhpp
• Stefan Borgwardt, Anke Hirsch, Alisa Kovtunova, and Frederik Wiehr. In the eye of the beholder: Which proofs are best? (extended abstract). In Franz Baader, editor, Workshop on Explainable Logic-Based Knowledge Representation (XLoKR’20), Online [Rhodes, Greece], September 13, 2020.
  https://lat.inf.tu-dresden.de/XLoKR20/XLoKRpaper395.pdf
  Extended version: doi:10.1007/978-3-031-21541-4_14
• Christian Alrabbaa, Franz Baader, Stefan Borgwardt, Patrick Koopmann, and Alisa Kovtunova. On the complexity of finding good proofs for description logic entailments. In Stefan Borgwardt and Thomas Meyer, editors, Proceedings of the 33rd International Workshop on Description Logics (DL’20), volume 2663 of CEUR Workshop Proceedings, Online [Rhodes, Greece], September 12, 2020.
  https://ceur-ws.org/Vol-2663/paper-1.pdf
• Stefan Borgwardt, Walter Forkel, and Alisa Kovtunova. Finding new diamonds: Temporal minimal-world query answering over sparse aboxes (extended abstract). In Stefan Borgwardt and Thomas Meyer, editors, Proceedings of the 33rd International Workshop on Description Logics (DL’20), volume 2663 of CEUR Workshop Proceedings, Online [Rhodes, Greece], September 12, 2020.
  https://ceur-ws.org/Vol-2663/abstract-5.pdf
  Extended version: doi:10.1007/978-3-030-31095-0_1
• Stefan Borgwardt, Anke Hirsch, Alisa Kovtunova, and Frederik Wiehr. In the eye of the beholder: Which proofs are best? In Stefan Borgwardt and Thomas Meyer, editors, Proceedings of the 33rd International Workshop on Description Logics (DL’20), volume 2663 of CEUR Workshop Proceedings, Online [Rhodes, Greece], September 12, 2020.
  https://ceur-ws.org/Vol-2663/paper-6.pdf
  Extended version: doi:10.1007/978-3-031-21541-4_14
• Frederik Wiehr, Anke Hirsch, Florian Daiber, Antonio Krüger, Ernie Chang, Vera Demberg, Alisa Kovtunova, Stefan Borgwardt, Marcel Steinmetz, and Jörg Hoffmann. Safe handover in mixed-initiative control for cyber-physical systems. In Susanne Boll, Philippe Palanque, Alexander Mirnig, Jessica Cauchard, Margaretha Lützhöft, and Michael S. Feary, editors, Proceedings of the CHI’20 Workshop on Designing Safety Critical Interactions: Hunting Down Human Error, Honolulu, USA, April 25, 2020.
  https://arxiv.org/abs/2010.10967
  Extended version: doi:10.1145/3462244.3479884

2019

• Franz Baader, Stefan Borgwardt, Walter Forkel, Alisa Kovtunova, Chao Xu, and Beihai Zhou. Temporalized ontology-mediated query answering under minimal-world semantics. In Franz Baader, Brigitte Grau, and Yue Ma, editors, Proceedings of the 2nd International Workshop on Hybrid Question Answering with Structured and Unstructured Knowledge (HQA’19), Marina del Rey, USA, November 19, 2019.
• Chao Xu, Walter Forkel, Stefan Borgwardt, Franz Baader, and Beihai Zhou. Automatic translation of clinical trial eligibility criteria into formal queries. In Martin Boeker, Ludger Jansen, Frank Loebe, and Stefan Schulz, editors, Proceedings of the 9th Workshop on Ontologies and Data in Life Sciencs (ODLS’19), part of The Joint Ontology Workshops (JOWO’19), volume 2518 of CEUR Workshop Proceedings, Graz, Austria, September 23, 2019.
  https://ceur-ws.org/Vol-2518/paper-ODLS13.pdf
• Stefan Borgwardt, İsmail İlkan Ceylan, and Thomas Lukasiewicz. Ontology-mediated query answering over log-linear probabilistic data (abstract). In Mantas Šimkus and Grant Weddell, editors, Proceedings of the 32nd International Workshop on Description Logics (DL’19), volume 2373 of CEUR Workshop Proceedings, Oslo, Norway, June 18, 2019.
  https://ceur-ws.org/Vol-2373/paper-35.pdf
  Extended version: doi:10.1609/aaai.v33i01.33012711
• Stefan Borgwardt and Walter Forkel. Closed-world semantics for conjunctive queries with negation over ${{E}{L}{H}}_{\perp }$ ontologies (extended abstract). In Mantas Šimkus and Grant Weddell, editors, Proceedings of the 32nd International Workshop on Description Logics (DL’19), volume 2373 of CEUR Workshop Proceedings, Oslo, Norway, June 18, 2019.
  https://ceur-ws.org/Vol-2373/paper-36.pdf
  Extended version: doi:10.1007/978-3-030-19570-0_24

2018

• Franz Baader, Stefan Borgwardt, and Walter Forkel. Patient selection for clinical trials using temporalized ontology-mediated query answering. In Franz Baader, Brigitte Grau, and Yue Ma, editors, Proceedings of the 1st International Workshop on Hybrid Question Answering with Structured and Unstructured Knowledge (HQA’18), Companion Volume of WWW’18, pages 1069–1074, Lyon, France, April 23, 2018. ACM.
  doi:10.1145/3184558.3191538

2017

• Franz Baader, Stefan Borgwardt, Patrick Koopmann, Ana Ozaki, and Veronika Thost. Metric temporal description logics with interval-rigid names (extended abstract). In Alessandro Artale, Birte Glimm, and Roman Kontchakov, editors, Proceedings of the 30th International Workshop on Description Logics (DL’17), volume 1879 of CEUR Workshop Proceedings, Montpellier, France, July 18, 2017.
  https://ceur-ws.org/Vol-1879/paper20.pdf
  Extended version: doi:10.1007/978-3-319-66167-4_4
• Franz Baader, Stefan Borgwardt, and Marcel Lippmann. Query rewriting for DL-Lite with $n$-ary concrete domains (abstract). In Alessandro Artale, Birte Glimm, and Roman Kontchakov, editors, Proceedings of the 30th International Workshop on Description Logics (DL’17), volume 1879 of CEUR Workshop Proceedings, Montpellier, France, July 18, 2017.
  https://ceur-ws.org/Vol-1879/paper29.pdf
  Extended version: doi:10.24963/ijcai.2017/109
• Stefan Borgwardt, Marco Cerami, and Rafael Peñaloza. Łukasiewicz fuzzy ${E}{L}$ is undecidable. In Alessandro Artale, Birte Glimm, and Roman Kontchakov, editors, Proceedings of the 30th International Workshop on Description Logics (DL’17), volume 1879 of CEUR Workshop Proceedings, Montpellier, France, July 18, 2017.
  https://ceur-ws.org/Vol-1879/paper27.pdf
  Extended version: doi:10.1016/j.ijar.2017.09.005
• Stefan Borgwardt, İsmail İlkan Ceylan, and Thomas Lukasiewicz. Ontology-mediated queries for probabilistic databases (extended abstract). In Alessandro Artale, Birte Glimm, and Roman Kontchakov, editors, Proceedings of the 30th International Workshop on Description Logics (DL’17), volume 1879 of CEUR Workshop Proceedings, Montpellier, France, July 18, 2017.
  https://ceur-ws.org/Vol-1879/paper17.pdf
  Extended version: doi:10.1609/aaai.v31i1.10680
• İsmail İlkan Ceylan, Stefan Borgwardt, and Thomas Lukasiewicz. Most probable explanations for probabilistic database queries (extended abstract). In Alessandro Artale, Birte Glimm, and Roman Kontchakov, editors, Proceedings of the 30th International Workshop on Description Logics (DL’17), volume 1879 of CEUR Workshop Proceedings, Montpellier, France, July 18, 2017.
  https://ceur-ws.org/Vol-1879/paper18.pdf
  Extended version: doi:10.24963/ijcai.2017/132

2016

• Stefan Borgwardt, Bettina Fazzinga, Thomas Lukasiewicz, Akanksha Shrivastava, and Oana Tifrea-Marciuska. Preferential query answering in the Semantic Web with possibilistic networks. In Gerhard Friedrich, Malte Helmert, and Franz Wotawa, editors, Appendix to the 39th German Conference on Artificial Intelligence (KI’16), volume 9904 of Lecture Notes in Artificial Intelligence, pages 264–270, Klagenfurt, Austria, September 26, 2016. Springer-Verlag. Extended abstract.
  doi:10.1007/978-3-319-46073-4
  Extended version: https://ijcai.org/Abstract/16/145
• Stefan Borgwardt and Rafael Peñaloza. Reasoning in expressive Gödel description logics. In Maurizio Lenzerini and Rafael Peñaloza, editors, Proceedings of the 29th International Workshop on Description Logics (DL’16), volume 1577 of CEUR Workshop Proceedings, Cape Town, South Africa, April 22, 2016.
  https://ceur-ws.org/Vol-1577/paper_2.pdf
  Extended version: doi:10.1007/978-3-319-24246-0_4

2015

• Stefan Borgwardt and Rafael Peñaloza. Reasoning in infinitely-valued $G\text{-}\Im {A}{L}{C}{Q}$. In Proceedings of the 3rd Workshop on Weighted Logics for AI (WL4AI’15), pages 2–8, Buenos Aires, Argentina, July 26, 2015.
  https://arxiv.org/abs/1509.08761
  Extended version: doi:10.1007/978-3-319-24246-0_4
• Franz Baader, Stefan Borgwardt, and Barbara Morawska. Dismatching and local disunification in ${E}{L}$ (extended abstract). In Santiago Escobar and Mateu Villaret, editors, Proceedings of the 29th International Workshop on Unification (UNIF’15), pages 13–18, Warsaw, Poland, June 28, 2015. Extended abstract.
  https://www.irif.fr/~treinen//unif/past/index.html
  Extended version: doi:10.4230/LIPIcs.RTA.2015.40
• Franz Baader, Stefan Borgwardt, and Barbara Morawska. Dismatching and local disunification in ${E}{L}$ (extended abstract). In Diego Calvanese and Boris Konev, editors, Proceedings of the 28th International Workshop on Description Logics (DL’15), volume 1350 of CEUR Workshop Proceedings, pages 30–33, Athens, Greece, June 7, 2015. Extended abstract.
  https://ceur-ws.org/Vol-1350/paper-07.pdf
  Extended version: doi:10.4230/LIPIcs.RTA.2015.40
• Stefan Borgwardt, Theofilos Mailis, Rafael Peñaloza, and Anni-Yasmin Turhan. Conjunctive query answering with finitely many truth degrees. In Diego Calvanese and Boris Konev, editors, Proceedings of the 28th International Workshop on Description Logics (DL’15), volume 1350 of CEUR Workshop Proceedings, pages 364–367, Athens, Greece, June 7, 2015. Extended abstract.
  https://ceur-ws.org/Vol-1350/paper-45.pdf
  Extended version: doi:10.1007/s13740-015-0055-y
• Stefan Borgwardt and Veronika Thost. Temporal query answering in ${E}{L}$. In Diego Calvanese and Boris Konev, editors, Proceedings of the 28th International Workshop on Description Logics (DL’15), volume 1350 of CEUR Workshop Proceedings, pages 83–87, Athens, Greece, June 7, 2015. Extended abstract.
  https://ceur-ws.org/Vol-1350/paper-14.pdf
  Extended version: https://ijcai.org/Abstract/15/399

2014

• Stefan Borgwardt, Marco Cerami, and Rafael Peñaloza. Many-valued horn logic is hard. In Thomas Lukasiewicz, Rafael Peñaloza, and Anni-Yasmin Turhan, editors, Proceedings of the 1st Workshop on Logics for Reasoning About Preferences, Uncertainty, and Vagueness (PRUV’14), volume 1205 of CEUR Workshop Proceedings, pages 52–58, Vienna, Austria, July 23, 2014.
  https://ceur-ws.org/Vol-1205/00010052.pdf
• Stefan Borgwardt, Felix Distel, and Rafael Peñaloza. Gödel description logics with general models. In Meghyn Bienvenu, Magdalena Ortiz, Riccardo Rosati, and Mantas Šimkus, editors, Proceedings of the 27th International Workshop on Description Logics (DL’14), volume 1193 of CEUR Workshop Proceedings, pages 391–403, Vienna, Austria, July 17, 2014. Poster paper.
  https://ceur-ws.org/Vol-1193/paper_2.pdf
• Stefan Borgwardt, José A. Leyva Galano, and Rafael Peñaloza. Gödel ${{F}{L}}_0$ with greatest fixed-point semantics. In Meghyn Bienvenu, Magdalena Ortiz, Riccardo Rosati, and Mantas Šimkus, editors, Proceedings of the 27th International Workshop on Description Logics (DL’14), volume 1193 of CEUR Workshop Proceedings, pages 71–82, Vienna, Austria, July 17, 2014.
  https://ceur-ws.org/Vol-1193/paper_3.pdf
  Extended version: doi:10.1007/978-3-319-11558-0_5
• Stefan Borgwardt. Fuzzy DLs over finite lattices with nominals. In Meghyn Bienvenu, Magdalena Ortiz, Riccardo Rosati, and Mantas Šimkus, editors, Proceedings of the 27th International Workshop on Description Logics (DL’14), volume 1193 of CEUR Workshop Proceedings, pages 58–70, Vienna, Austria, July 17, 2014. Distinguished Student Paper Award.
  https://ceur-ws.org/Vol-1193/paper_4.pdf
  Extended version: https://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-145311

2013

• Stefan Borgwardt, Marcel Lippmann, and Veronika Thost. Temporal query answering in DL-Lite. In Thomas Eiter, Birte Glimm, Yevgeny Kazakov, and Markus Krötzsch, editors, Proceedings of the 26th International Workshop on Description Logics (DL’13), volume 1014 of CEUR Workshop Proceedings, Ulm, Germany, July 23, 2013. Distinguished Student Paper Award.
  https://ceur-ws.org/Vol-1014/paper_8.pdf
  Extended version: doi:10.1007/978-3-642-40885-4_11
• Stefan Borgwardt and Rafael Peñaloza. About subsumption in fuzzy ${E}{L}$. In Thomas Eiter, Birte Glimm, Yevgeny Kazakov, and Markus Krötzsch, editors, Proceedings of the 26th International Workshop on Description Logics (DL’13), volume 1014 of CEUR Workshop Proceedings, Ulm, Germany, July 23, 2013. Poster paper.
  https://ceur-ws.org/Vol-1014/paper_48.pdf
  Extended version: https://ijcai.org/Abstract/13/123

2012

• Franz Baader, Stefan Borgwardt, and Barbara Morawska. Recent advances in unification for the ${E}{L}$ family. In Santiago Escobar, Konstantin Korovin, and Vladimir Rybakov, editors, Proceedings of the 26th International Workshop on Unification (UNIF’12), volume 24 of EasyChair Proceedings in Computing, pages 1–6, Manchester, UK, July 1, 2012.
  doi:10.29007/q5px
• Franz Baader, Stefan Borgwardt, Julian Alfredo Mendez, and Barbara Morawska. UEL: Unification solver for ${E}{L}$. In Yevgeny Kazakov, Domenico Lembo, and Frank Wolter, editors, Proceedings of the 25th International Workshop on Description Logics (DL’12), volume 846 of CEUR Workshop Proceedings, pages 26–36, Rome, Italy, June 7, 2012.
  https://ceur-ws.org/Vol-846/paper_8.pdf
• Franz Baader, Stefan Borgwardt, and Barbara Morawska. A goal-oriented algorithm for unification in ${E}{L}$ w.r.t. cycle-restricted TBoxes. In Yevgeny Kazakov, Domenico Lembo, and Frank Wolter, editors, Proceedings of the 25th International Workshop on Description Logics (DL’12), volume 846 of CEUR Workshop Proceedings, pages 37–47, Rome, Italy, June 7, 2012.
  https://ceur-ws.org/Vol-846/paper_1.pdf
  Extended version: doi:10.1007/978-3-642-35101-3_42
• Stefan Borgwardt, Felix Distel, and Rafael Peñaloza. Gödel negation makes unwitnessed consistency crisp. In Yevgeny Kazakov, Domenico Lembo, and Frank Wolter, editors, Proceedings of the 25th International Workshop on Description Logics (DL’12), volume 846 of CEUR Workshop Proceedings, pages 103–113, Rome, Italy, June 7, 2012.
  https://ceur-ws.org/Vol-846/paper_13.pdf
• Stefan Borgwardt and Rafael Peñaloza. Non-Gödel negation makes unwitnessed consistency undecidable. In Yevgeny Kazakov, Domenico Lembo, and Frank Wolter, editors, Proceedings of the 25th International Workshop on Description Logics (DL’12), volume 846 of CEUR Workshop Proceedings, pages 411–421, Rome, Italy, June 7, 2012. Poster paper.
  https://ceur-ws.org/Vol-846/paper_14.pdf

2011

• Stefan Borgwardt and Rafael Peñaloza. Finite lattices do not make reasoning in ${A}{L}{C}{I}$ harder. In Fernando Bobillo, Rommel Carvalho, Paulo C. G. da Costa, Claudia d’Amato, Nicola Fanizzi, Kathryn B. Laskey, Kenneth J. Laskey, Thomas Lukasiewicz, Trevor Martin, Matthias Nickles, and Michael Pool, editors, Proceedings of the 7th International Workshop on Uncertainty Reasoning for the Semantic Web (URSW’11), volume 778 of CEUR Workshop Proceedings, pages 51–62, Bonn, Germany, October 26, 2011.
  https://ceur-ws.org/Vol-778/paper5.pdf
  Extended version: doi:10.1007/978-3-319-13413-0_7
• Franz Baader, Nguyen Thanh Binh, Stefan Borgwardt, and Barbara Morawska. Computing local unifiers in the description logic ${E}{L}$ without the top concept. In Franz Baader, Barbara Morawska, and Jan Otop, editors, Proceedings of the 25th International Workshop on Unification (UNIF’11), pages 2–8, Wrocław, Poland, July 31, 2011.
  Extended version: doi:10.1215/00294527-3555507
• Franz Baader, Nguyen Thanh Binh, Stefan Borgwardt, and Barbara Morawska. Unification in the description logic ${E}{L}$ without the top concept. In Riccardo Rosati, Sebastian Rudolph, and Michael Zakharyaschev, editors, Proceedings of the 24th International Workshop on Description Logics (DL’11), volume 745 of CEUR Workshop Proceedings, pages 26–36, Barcelona, Spain, July 13, 2011.
  https://ceur-ws.org/Vol-745/paper_5.pdf
  Extended version: doi:10.1215/00294527-3555507
• Stefan Borgwardt and Rafael Peñaloza. Fuzzy ontologies over lattices with t-norms. In Riccardo Rosati, Sebastian Rudolph, and Michael Zakharyaschev, editors, Proceedings of the 24th International Workshop on Description Logics (DL’11), volume 745 of CEUR Workshop Proceedings, pages 70–80, Barcelona, Spain, July 13, 2011.
  https://ceur-ws.org/Vol-745/paper_1.pdf
  Extended version: doi:10.1016/j.ijar.2013.07.006

Theses

• Stefan Borgwardt. Fuzzy description logics with general concept inclusions. PhD thesis, Technische Universität Dresden, May 23, 2014. Evaluated summa cum laude.
  https://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-145311
• Stefan Borgwardt. The infimum problem as a generalization of the inclusion problem for automata. Diploma thesis, Technische Universität Dresden, October 13, 2010. Grade 1.1.
  https://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa2-888026
• Stefan Borgwardt. Bindungen. Diploma thesis, Technische Universität Dresden, July 15, 2010. In German. Grade 1.0.
  https://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa2-892303