General Formal Ontology (GFO)
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General Formal Ontology

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> Publications
> Axiomatizations and Implementations
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> Brief History


The General Formal Ontology is a top-level ontology which is being developed by Onto-Med. It includes elaborations of categories like objects, processes, time and space, properties, relations, roles, functions, facts, and situations. Moreover, we are working on an integration with the notion of levels of reality in order to more appropriately capture entities in the material, mental, and social areas. Outstanding features of GFO are:

  • coherent integration of objects and processes (based on a novel category of persistants)
  • time and space entities as entities sui generis, and the relation of coincidence
  • a category of situoids, comprehensible wholes of the most independent character
  • elaborate accounts of functions and roles
  • openness regarding philosophical positions such as realism, conceptualism, or nominalism by the provision of different kinds of categories as universals, concepts, or symbolic structures


Onto-Med Report Series on GFO

The major descriptive source for GFO is a series of Onto-Med Reports. As this work progresses continuously and in irregular intervals, draft versions are also provided. These may exhibit some technical deficiencies (e.g., few missing references, "empty sections" indicating areas under research). Nevertheless, they best reflect the continuing development of GFO during report releases.

The series comprises reports with respect to three components: Part I (Basic Principles) sets forth the logical and philosophical basic assumptions and methods, and presents a conceptual account of the General Formal Ontology (GFO) in some detail. Part II (Axiomatics and Ontology Languages) presents a full axiomatization of GFO, as well as a library of ontology languages, and several tools for meta-logical analyses of formal axioms. In Part III (Applications) several applications of GFO are collected and presented. Currently, only Part I is available, whereas Part II and III are forthcoming.

The following is the general form of citation for Part I, where the corresponding version and, for releases, the number in the series should be added.

Herre, H.; Heller, B.; Burek, P.; Hoehndorf, R.; Loebe, F. & Michalek, H.. General Formal Ontology (GFO): A Foundational Ontology Integrating Objects and Processes. Part I: Basic Principles. Research Group Ontologies in Medicine (Onto-Med), University of Leipzig.


  • Latest intermediate revision: Version 1.0.1, Draft, 14.02.2007 [PDF]   (changes: primarily sect. 2.3, 3.5, 3.6, 8 and 16)
  • Latest released revision: Version 1.0, Onto-Med Report Nr. 8, 01.07.2006 [PDF] [HTML]

Other publications on GFO

Heller, B., Herre, H. 2004. Ontological Categories in GOL. Axiomathes 14(1):57-76 Kluwer Academic Publishers. [PDF]

Heller, B. & Herre, H. 2003. Formal Ontology and Principles of GOL. Onto-Med Report Nr. 1. Research Group Ontologies in Medicine (Onto-Med), University of Leipzig.

Axiomatizations and Implementations

Partial axiomatizations of GFO in the language of first-order logic exist, but are not yet available to the public.

In early 2006, we started to develop an OWL version of GFO in parallel, in the context of the GFO-Bio project. Since August 2006, the first release can be found at

The work on GFO and its OWL version continues; the latest CVS version is hosted as a Savannah project. Thus there is a ViewCVS, and in order to link to the latest version please use gfo.owl from HEAD.

Mailing List

We invite you to send us your questions or provide feedback on GFO and top-level ontologies in general, experience with using GFO, usability of the available material, etc. Please send a mail to the public mailing list, i.e., address mails to . You may also have a look into the archives.

Brief History

Work on GFO has started in 1999 in the context of the GOL project (General Ontological Language). Meanwhile, several directions of research have been recognized and divided the initial project, such that GFO is now one component of a larger framework. Work on GFO remains in progress, because the development of top-level ontologies is a long-term research effort.


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