Data and Knowledge Group

― Knowledge Representation and Reasoning

Birte Glimm

Research Assistant


My main research interests are knowledge representation and reasoning. In particular, I enjoy developing and implementing algorithms for reasoning in expressive description logics. Most recently, I implemented a datatype checker for the HermiT reasoner that allows for reasoning over concrete domains such as Strings, Integers, etc. I have also developed algorithms for conjunctive queries in the Description Logics SHIQ and SHOQ together with Ian Horrocks, Uli Sattler, and Carsten Lutz. SHIQ is the Description Logic that underlies OWL Lite, which is one of the W3C standardised Web Ontology Languages. Conjunctive queries are well known in the database community, which motivated the decision to study whether conjunctive query entailment is also decidable for expressive Description Logic knowledge bases. I also analysed the complexity of the developed algorithms and proved 2ExpTime upper bounds. For SHIQ, Carsten Lutz showed that the bound is tight and that conjunctive queries for SHIQ are, therefore, strictly harder than the standard reasoning tasks, such as knowledge base consistency or instance retrieval, which are ExpTime-complete. Recently, I have worked with Yevgeny Kazakov on the complexity of expressive Description Logics with role conjunctions, which is a problem closely related to query answering. Our work shows, among other things, that conjunctive queries for SHOIQ, which underlies the OWL DL standard, are at least N2ExpTime-hard. Decidability of this problem is, however, still open and part of my future work.


Currently, I work as a research assistant in the Department of Computer Science of the University of Oxford. I work in the Information Systems group, mainly on developing algorithms for automated reasoning in expressive Description Logics and on the implementation of the HermiT reasoner. You can contact me at firstname.lastname at

From September 2004 until September 2007 I was a PhD student in the Information Management Group at the University of Manchester and I was honoured with the Best Thesis Award from the School of Computer Science at Manchester University in 2008. The topic of my PhD thesis is Querying Description Logic Knowledge Bases and I was jointly supervised by Prof. Ian Horrocks and Prof. Ulrike Sattler. From September 2001 until July 2004 I studied Computer Science in the Hamburg University of Applied Sciences and I received my bachelor degree with an award for the best degree. The topic of my bachelor report was "A Query Language for Web Ontologies" and I wrote the report as a visiting student at the University of Manchester.

Before studying Computer Science, I worked for 3.5 years in Industry and did another degree in Communication Design. My full CV in PDF format is available here.


Best Thesis Award from the University of Manchester

Best Student Award for my bachelor degree from the University of Applied Sciences Hamburg

Scholarship from the Foundation of German Bisuness (Stiftung der Deutschen Wirtschaft)

Recent Publications

Reasoning-Supported Interactive Revision of Knowledge Bases by Nadeschda Nikitina, Sebastian Rudolph, and Birte Glimm. In Proceedings of the 22nd International Joint Conference on Artificial Intelligence (IJCAI 2011). AAAI Press/The MIT Press. 2011. To Appear

Status QIO: An Update by Birte Glimm, Yevgeny Kazakov and Carsten Lutz. The University of Oxford. 2011


Birte Glimm


Research Assistant



Contact Information

+44 (0)1865 283529

Room 306, Wolfson Building, Parks Road
Oxford OX1 3QD


CV in PDF format

HermiT reasoner


New Positions!

The KRR group has new postdoctoral positions available! Research topic includes Ontology, Knowledge Graph, Semantic Web, Logics, as well as the interdisciplinary between them and machine learning. Send your CV to Ian or Bernardo. [added on 26/11/2019]

In-Use Track Best Student Paper in ISWC'19>

The paper "Knowledge Graph Embedding for Ecotoxicological Effect Prediction" gets In-Use Track Best Student Paper in ISWC'19. The work was done when the first student author Erik B. Myklebust was visiting the KRR group, with Jiaoyan Chen.

3 Paper accepted in AAAI'18

Three papers co-authored by the KRR group have been accepted in AAAI'18:
- "Stream Reasoning in Temporal Datalog" by A. Ronca, M. Kaminski, B. Cuenca Grau, B. Motik, and I. Horrocks;
- "Optimised Maintenance of Datalog Materialisations" by P. Hu, B. Motik, and I. Horrocks; and
- "Goal-Driven Query Answering for Existential Rules with Equality" by M. Benedikt, B. Motik, and E. Tsamoura.

Professor Ian Horrocks is a new honorary doctorate at University of Oslo, Faculty of Mathematics and Natural Sciences

Professor Ian Horrocks received an honorary doctorate from the University of Oslo.

Best paper award at IJCAI'17

The paper entitled "Foundations of Declarative Data Analysis Using Limit Datalog Programs" and authored by M. Kaminski, B. Cuenca Grau, B. Motik, E. V. Kostylev, and I. Horrocks received the best paper award at the 26th International Joint Conference on Artificial Intelligence (IJCAI'17).

3 papers accepted in IJCAI'17

Three papers co-authored by the KRR group have been accepted in IJCAI'17:
- "Query Reformulation: Theory and Practice" by M. Benedikt, E. V. Kostylev, F. Mogavero, and E. Tsamoura;
- "Foundations of Declarative Data Analysis Using Limit Datalog Programs" by M. Kaminski, B. Cuenca Grau, B. Motik, E. V. Kostylev, and I. Horrocks; and
- "The Bag Semantics of Ontology-Based Data Access" by C. Nikolaou, E. V. Kostylev, G. Konstantinidis, M. Kaminski, B. Cuenca Grau, and I. Horrocks.

Paper accepted in PODS'17

The paper entitled "Benchmarking the chase" authored by Michael Benedikt, George Konstantinidis, Giansalvatore Mecca, Boris Motik, Paolo Papotti, Donatello Santoro, and Efthymia Tsamoura has been accepted in PODS'17.

Andrew Bate defends his PhD Thesis

Andrew Bate has successfully defended his PhD Thesis on Consequence Based Reasoning. Congratulations to Dr. Andrew Bate!

Best applications paper award at ISWC'16

Our paper entitled "Semantic Technologies for Data Analysis in Health Care" received the Best Applications Paper Award at the International Semantic Web Conference (ISWC 2016).

4 papers accepted in ISWC'16

Four papers authored by the KRR group have been accepted in the International Semantic Web Conference (ISWC 2016).

Best paper award at ICDT'16

Mark Kaminski and Egor Kostylev received the best paper award at ICDT 2016 for their paper entitled "Beyond Well-Designed SPARQL".