From Provenance WG Wiki

Contents 1 Intro 2 Current Issues 2.1 Which owl should be returned when dereferencing 2.1.1 Solution 1: Merge all owl files into one namespace owl 2.1.2 Solution 2: Use owl:import 2.1.3 Solution 2.1 Use owl:import, but merge PROV-O

Intro

This page describes the management (and issues around) of the prov namespace.

The namespace is:

• http://www.w3.org/ns/prov#

Some requirements:

• the namespace should dereference to appropriate serialization based on accept headers. Some examples
  • curl -H "Accept:text/html" -L http://www.w3.org/ns/prov#
  • curl -H "Accept:application/rdf+xml" -L http://www.w3.org/ns/prov#
  • curl -H "Accept:text/turtle" -L http://www.w3.org/ns/prov#
• In the html page returned, we should provide a glossary of terms with appropriate links to the various specifications.
• The html should be embedded with RDFa

Current Issues

Which owl should be returned when dereferencing

• This is ISSUE-440
• At theJuly 5th telco, we discussed two possible solutions described below:

Solution 1: Merge all owl files into one namespace owl

Here the idea is that each note would maintain a separate owl file. For example sake let's use the following names:

• ProvenanceOntology.owl - the file containing owl definitions of terms in prov-o
• prov-aq.owl - the file containing owl definitions of terms in the paq
• prov-dict.owl - the file containing the owl definitions of terms in prov dictionaries

The proposal would be that this would be merged into a single file

• prov.owl

The single file would contain concatenated sections delimitated by comments e.g.

# ...
prov:Entity a owl:Class .
# ...
##This section of the prov.owl contains terms from prov-aq
prov:hasProvenanceService a owl:ObjectProperty .
# ...

In addition we would add provenance information identifying where the information was retrieved from

<> prov:wasDerivedFrom <http://dvcs.w3.org/hg/prov/raw-file/42195124779a/ontology/ProvenanceOntology.owl> . 

Stian: Should not the above go to the OWL file from the timestamped REC?

Upsides

• Machine readable information for all terms in the namespace can be easily retrieved

Downsides

• Creates a monolithic file
• Some provenance is lost
• Confusing to know what is part of recommendation or not
• Confusing which is the official recommendation, prov.owl or ProvenanceOntology.owl - gut instinct would be that the official is what you get from resolving namespace!

Solution 2: Use owl:import

Here we define a single owl file that imports the necessary information from all the separate owl files. Something like:

<> owl:imports <http://dvcs.w3.org/hg/prov/raw-file/42195124779a/ontology/ProvenanceOntology.owl> .
<> owl:imports <http://dvcs.w3.org/hg/prov/raw-file/98870b4c796c/ontology/prov-dictionary.owl> .

Stian: Should not the above URLs point to the OWLs of the timestamped REC and Note's folders?

Upsides

• Creates a simple file with clear distinction between which terms are defined by which notes

Downsides

• No simple dereferencability
• Requires owl reasoning

Solution 2.1 Use owl:import, but merge PROV-O

This hybrid solution is a single OWL file with the content of ProvenanceOntology.owl (PROV-O) - but with the additional owl:imports for the modules. It will include provenance to the OWL of the official REC that it is derived from.

## Terms declared here are copied verbatim from the PROV-O recommendation
<> a owl:Ontology ;
   prov:hadPrimarySource <http://www.w3.org/TR/2012/WD-prov-o-20120799/ProvenanceOntology.owl> .
# ...
prov:Entity a owl:Class .
# ...
## This namespace also covers terms from notes which
## don't form part of the PROV-O recommendation.
#
<> owl:imports <http://www.w3.org/TR/prov-aq/prov-aq.owl>,
               <http://www.w3.org/TR/prov-collections/prov-collections.owl> .

Upsides

• Distinguishes 'official' bit (PROV-O REC) from additional modules (notes)
• Does not require OWL reasoning for official terms
• Stronger metaprovenance

Downsides

• Requires OWL reasoning for notes.