Abstract
OWLlink provides a declarative interface for – among other
things – asserting OWL axioms to a Knowledge Base (KB) of an
OWL reasoner. This OWLlink extension adds the ability to retract
previously asserted axioms from KBs.
This section describes the status of this document at the
time of its publication. Other documents may supersede this
document. A list of current W3C publications can be found in the
W3C technical reports index at
http://www.w3.org/TR/.
This document is a part of the OWLllink
Submission which comprises eight documents:
- OWLlink:
Structural Specification
- OWLlink: HTTP/XML
Binding
- OWLlink:
HTTP/Functional Binding
- OWLlink:
HTTP/S-Expression Binding
- OWLlink Extension:
Retraction (this document)
- OWLlink
Extension: Retraction HTTP/XML Binding
- OWLlink
Extension: Retraction HTTP/Functional Binding
- OWLlink
Extension: Retraction HTTP/S-Expression Binding
Earlier drafts of the OWLlink specification have been published by the informal
OWLlink working group at
http://www.owllink.org.
By publishing this document, W3C acknowledges that the Submitting
Members have made a formal Submission request to W3C for
discussion. Publication of this document by W3C indicates no
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allocating any resources to the issues addressed by it. This
document is not the product of a chartered W3C group, but is
published as potential input to the W3C Process. A W3C Team
Comment has been published in conjunction with this Member
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the requirements associated with Member Submissions of section
3.3 of the W3C Patent Policy. Please consult the complete
list of acknowledged W3C Member
Submissions.
1 Introduction
The OWLlink core interface [OWLlink Structural
Specification] relies on a certain kind of incremental
batch-oriented reasoning procedure. After submission of a set of
axioms a client can pose some queries, add further axioms, query
again, and so on. Deletion of axioms is ony possible by releasing a
KB and re-submission of axioms. This document describes the
retraction extension of OWLlink which allows to retract previously
told KB fragments on axiom level.
This extension is based on the same preliminaries than the
OWLlink core.
2 Retraction
The Retract request is the inverse
command to Tell (cf. Section ‘4
Tells’ [OWLlink Structural
Specification]) and takes a set of OWL 2 axioms (cf.
Section ‘9 Axioms’ [OWL 2 Structural
Specification]) and removes them from the respective KB
as shown in Figure 1. The removal must be
sensitive to the rules of structural equivalence of OWL 2. That is,
an axiom can only be removed from a KB if and only if the KB
contains an axiom which is structural equivalent to the one given
in the retraction request. A server must not respond with an error
if a KB does not contain a structurally equivalent axiom but is
free to provide a warning. If all axioms of a retraction request
are successfully removed from the KB, the server has to respond
with an OK response.
Figure 1. Retraction Request (the
Tell request is rendered
semi-transparently to show the symmetry)
3 References
- [OWLlink
Structural Specification]
- OWLlink:
Structural Specification Document included in the
present W3C Member Submission.
- [OWL 2
Specification]
- OWL 2 Web
Ontology Language: Structural Specification and Functional-Style
Syntax Boris Motik, Peter F. Patel-Schneider, Bijan
Parsia, eds. W3C Recommendation, 27 October 2009, http://www.w3.org/TR/2009/REC-owl2-syntax-20091027/.
Latest version available at http://www.w3.org/TR/owl2-syntax/.