Torsten Hahmann

PhD Candidate and Research Assistant with Michael Gruninger
University of Toronto, Department of Computer Science
Knowledge Representation Group and Semantic Systems Lab


Research & Publications Teaching CV Contact

Research Interests

I am generally interested in everything that involves knowledge representation (in particular reprsentations of space), automated reasoning, logic, and commonsense representations and reasoning. Some of my current research activities resolve around two areas:

Spatial (and Spatio-Temporal) Representation and Reasoning

  • Qualitative Spatial Reasoning (QSR) in general
  • Qualitatitive theories of multidimensional, commonsensical space
  • Mereotopologies (region-based QSR) and point-free ('pointless') representations of space and their axiomatization in first-order theories
  • Algebraic and topological representation of ontologies mereotopology

    • (First-order) Ontologies

  • Ontology Repositories of first-order ontologies
  • Modularization of ontologies, hierarchies of ontologies
  • Spatial ontologies and ontologies for Geographic Information Systems (GIS), manufacturing, and hydrogeology
  • Semantic integration with ontologies
  • (Semi-)automated verification of first-order ontologies
  • Automated reasoning with first-order ontologies
  • Common Logic

    • Others

  • Automated theorem proving and model finding/generation
  • Semantic Integration based on ontologies
  • Semantic Web Services, Automated Web Service Composition


    • Publications

    You can find a more detailed list with explanations and accompanying presentations here


  • First-order ontologies of space and their semantic integration

    • T. Hahmann, B. Brodaric: The Void in Hydro Ontology.  In: Proc. of the 7th Int. Conference on Formal Ontology in Information Systems (FOIS-2012), 2012. IOS Press, to appear.  Preprint PDF

    T. Hahmann, M. Gruninger: Complementation in representable theories of region-based space.  Accepted for publication by Notre Dame Journal of Formal Logic, 2012.  Preprint PDF

    T. Hahmann, M. Gruninger: Multidimensional Mereotopology with Betweenness.  In: Proc. of the Int. Joint Conference on Artificial Intelligence (IJCAI 2011), 2011. AAAI Press.  PDF

    T. Hahmann, M. Gruninger: A Naive Theory of Dimension for Qualitative Spatial Relations. In: Proc. of the Symposium on Logical Formalizations of Commonsense Reasoning (CommonSense 2011), AAAI Spring Symposium, 2011. AAAI Press. PDF

    T. Hahmann, M. Gruninger: Region-based Theories of Space: Mereotopology and Beyond.  In: S. Hazarika (ed.): Qualitative Spatio-Temporal Representation and Reasoning: Trends and Future Directions. IGI Publishing, 2012 (to appear).  Preprint PDF (Qualifying Exam Report)

    T. Hahmann, M. Gruninger: Detecting Physical Defects: A Practical 2D-Study of Cracks and Holes.  In: Proc. of AAAI Spring Symposium on Benchmarking of Qualitative Spatial and Temporal Reasoning Systems, 2009. AAAI Press.  PDF



  • Model-theory for analysis of qualitative spatial theories

    • M. Winter, T. Hahmann, M. Gruninger: Stonian p-Ortholattices: A new approach to the mereotopology RT0.  Submitted to Annals of Artificial Intelligence and Mathematics, 2011

    M. Winter, T. Hahmann, M. Gruninger: On the Skeleton of Stonian p-Ortholattices. In: Proc. of the 11th Int. Conference on Relational Methods in Computer Science (RelMiCS/AKA-09), 2009. LNCS 5827, Springer, pp. 351--365. Preprint PDF

    T. Hahmann, M. Winter, M. Gruninger: Stonian p-Ortholattices: A new approach to the mereotopology RT0.  Artificial Intelligence 173, 2009, pp. 1424-1440. DOI:10.1016/j.artint.2009.07.001  PDF

    T. Hahmann, M. Gruninger: A Model-Theoretic Characterization of Asher and Vieu's Ontology of Mereotopology.  In: Proc. of the 11th Int. Conference on Knowledge Representation and Reasoning (KR-2008), 2008. AAAI Press, pp. 263--273.  PDF

    T. Hahmann: Model-Theoretic Analysis of Asher and Vieu's Mereotopology, M.Sc. thesis, 2008. PDF



  • Modularization of ontologies, hierarchies of ontologies

    • M. Gruninger, T. Hahmann, A. Hashemi, D. Ong, A. Ozgovde: Modular First-Order Ontologies via Repositories.  Accepted by Special Issue on Modular Ontologies, Applied Ontology, April 2012.

    M. Gruninger, T. Hahmann, M. Katsumi: Exploiting Modularity for Ontology Verification.  In: 5th Int. Workshop on Modular Ontologies (WoMo 2011), 2011. Frontiers in Artificial Intelligence and Applications Series, IOS Press.  Preprint PDF

    M. Gruninger, T. Hahmann, A. Hashemi, D. Ong: Ontology Verification with Repositories.  In: Proc. of the 6th Int. Conference on Formal Ontology in Information Systems (FOIS-2010), 2010. IOS Press, pp. 317--330.  Preprint PDF



  • Semantic Web Services and Web Service Composition

    • G. Laures, H. Meyer, T. Hahmann, J. Möller, P. Sommer: Evaluation von Open Source Produkten zur Ausführung Web Service-basierter Geschäftsprozesse.  In: open.bpm 2006 Workshop at EMISA 2006, 2006.  PDF (English version)

    T. Hahmann, J. Möller, P. Sommer, B. Peisl, A. Wahler:  An Adaptive Solution for Internet Services' Supply Chains.  In: Semantic Content Engineering, Schriftenreihe Informatik, No. 17 (Proceedings of the Semantics 2005), 2006. Trauner, pp. 65--80. PDF

    Steinert, B., Möller, J., Sommer, P., Steinhauer, S., Hüttenrauch, S., Queck, T., Hahmann, T.: Semantic SOA - Realization of the Adaptive Services Grid. Bachelor project report, Hasso-Plattner-Institute for Software Systems Engineering at the University of Potsdam, 2006. PDF (Introduction) PDF (Dynamic Supply Chain Scenario)