Hets - the Heterogeneous Tool Set
Copyright(c) Otto-von-Guericke University of Magdeburg
LicenseGPLv2 or higher, see LICENSE.txt
Safe HaskellSafe



The OWL2 directory contains the OWL2 instance of Logic.Logic. The data for this instance is found in OWL2.Logic_OWL2.

Abstact Syntax

The syntax for OWL2 is represented using Haskell datatypes. It is defined both in OWL2.AS - which contains the entities and expressions (http://www.w3.org/TR/owl2-syntax/) and in OWL2.MS - which contains the frames (http://www.w3.org/TR/owl2-manchester-syntax/). As the official Manchester Syntax cannot express some of the valid OWL2 axioms, the Haskell datatypes for frames were extended to also accomodate these.


The parsing of an OWL ontology happens in two main steps. First, the ontology is converted to XML, using the Java parser found in "OWL2.java". Then, the XML is parsed into the Haskell datatypes (see OWL2.XML). The top-level function which combines the two steps is found in OWL2.ParseOWLAsLibDefn.

The parser for the Het-CASL representation is found in OWL2.Parse and OWL2.ManchesterParser which take as argument an ontology in our extended Manchester Syntax and convert it into the Haskell datatypes.

Pretty printing

This is done in OWL2.Print (for the "AS.hs" datatypes) and in OWL2.ManchesterPrint (fot the "MS.hs" datatypes). The output is written in our extended Manchester Syntax.

A LaTeX output is not available, yet.

Static Analysis

The file OWL2.StaticAnalysis repairs the ontology after parsing and then produces the final axioms and signature needed for hets analysis.


There are two of these for OWL2, namely Pellet and FACT++, written in Java. The call for them happens in OWL2.ProvePellet and OWL2.ProveFact. The input for the provers is XML syntax, which comes from OWL2.XMLConversion. The conservativity check is implemented in OWL2.Conservativity and uses the Java- written locality checker.


There are three implemented comorphsims: from OWL2 to CASL and Common Logic and from DMU to OWL2.

Profiles and sublogics

There are three OWL2 profiles: EL, QL and RL. In OWL2.Profiles, an ontology is taken as argument and analysed, in order to see in which of the profiles it fits, while in OWL2.Sublogics, the reasoning complexity of the ontology is computed.


OWL2.Function provides a class for functions which go through all the Haskell datatypes and which are structurally equivalent (except maybe on what they do with the IRIs or entities). Currently, morphism mapping, prefix renaming and IRI expansion are implemented there.

OWL2.ColimSign and OWL2.Taxonomy provide signature colimits and taxonomy extraction, respectively.