Category Archives: ontology

A Conversation between SNAP and CIDOC-CRM

SNAP:DRGN & CIDOC-CRM conversation
Friday, May 15, 2015: King’s College London

Attending: Gabriel Bodard (GB), Arianna Ciula (AC), Øyvind Eide (OE), Faith Lawrence (FL), Christian-Emil Ore (CEO), Paul Rissen (PR), Valeria Vitale (VV), Hafed Walda (HW).
Apologies: John Bradley, Steve Stead.
Minutes: GB.

We have three main topics of discussion:

  1. personal relationships (the SNAP “bond” ontology);
  2. co-references (and the inferences that derive from them);
  3. SNAP use of ontologies, and mapping to CRM.
1. Personal relationships/bonds
  • CEO: The CRM defines several types of relationship (e.g. event, group, unilateral, family)
  • GB: SNAP will eventually need to cover many more than just family/household relationships, as we currently have in the ontology
  • OE: Is the aim to map all SNAP relationships to the CRM ontology, so we can always represent SNAP in CRM?
  • FL: gave a summary of snap ontology
    • (digression on equivalences between [lawd|crm|foaf|snap|etc.]:Person; is this a union set, rather than a single overlapping definition?)
    • dual-classes of relationships: serious/casual/legally recognized; social contracts; intimate; household; foster/adopted/inlaw/claimed;
    • gender (and other assumptions) not modelled in top-level classes, but could (maybe should) be?
    • CEO: we can model all of these with group relationships, and then type them. Maybe we should make a recommendation for extending CRM with SNAP classes?
    • GB: can we model non-family relationships (at the top-level)?
      • [Not currently.]
    • CEO: We should probably leave events out of the typology for now.
    • VV: How can “ContractualRelationship” and “Relationship” be siblings?
      • (GB: rename “Rel” ~~> “QualifierRel”)
    • GB: then let’s just list all the new non-family relationships we need, and worry about grouping them (or not) later.
  • OE: Suggest a follow-up meeting on CRM-INF (with Steve Stead, Dominic Oldman and Hugh Cayless).
  • PR: BBC programmes ontology defines relationships by membership to groups
    • could build on snap bonds for new relationships; useful for scholarly/journalistic claims, inference etc.
2. Co-references–both unambiguous and suggested (and inference)
  • OE: distinguishing explicit and implicit co-reference:
    • implicit co-reference is what all scholarly systems do, x=y.
    • explicit co-reference requires attributing statement to someone
    • a negative co-reference has no common target
    • do co-references need a target?
    • CEO: CRM doesn’t model identity, per se; two entities with different ids are therefore two different entities. CRM can’t express conflicting/untrue information.
    • AC: it’s the expressing of conflicting opinions that is the problem there, if you want to keep both.
    • HW: is identity a combination of person and context?
      • CEO: They have different identifiers/are in different data-spaces.
    • OE: SNAP needs to make explicit co-reference statements (with “belief system” over the top). Do we want fuzzy reliability values on them? (GB: no!)
3. SNAP ontology(ies)
  • AC: lawd:hasAttestation/hasCitation == crm:isReferredToBy ?
  • AC: lawd:nameAttestation == crm:appellation ?
  • AC: CRM-inf might be more useful for Scenario 3 (unambiguous and unproblematic co-reference) than Scenario 4 (scholarly commentary about co-references/relationship), because CRM is a bit deterministic.

The Old Classes vs Properties Debate (or Relationships Are Hard, Part 2)

One of the decisions that has to be made when creating an ontology is which concepts you encode as classes and which you encode as properties of those classes. One of the difficulties is that there is no overarching ‘right answer’ (although there are wrong ones) to how you should model your domain, in has to be decided on a case-by-case basis of what works best for the type of world view that you are trying to encapsulate within your model. This post is a request for feedback to help us decide which model works best for both the project and the wider community. Continue reading The Old Classes vs Properties Debate (or Relationships Are Hard, Part 2)

Fluffy dates and associated places

One of the conversations that it was really useful to hash out in person and with the involvement of so many experts and interested parties present at the workshop a couple weeks ago, was the question of how the SNAP:DRGN Cookbook should recommend contributing person-datasets represent date information.

It has been our working assumption that the minimalist information SNAP is ingesting would optionally include a single, undifferentiated, very crudely recorded date associated with  person. (By the same token, any place information associated with a person would be given only in very blunt form, inasmuch as it serves almost as an extra name, epithet or indentifier for a person. Further more granular place association, à la Pelagios, might be included in the original prosopography, and/or in the exposed RDF serialization of said dataset, but SNAP will only expect and take advantage of associated place in the most abstract form.) The argument may be at its clearest with respect to dating, however, partly because there are so many strong arguments for including more granular and semantic date information in a prosopographic dataset. Continue reading Fluffy dates and associated places

Workshop slides and recap

At last week’s SNAP workshop in King’s College London, we had a very successful and enjoyable two-day meeting, introducing the principles of and the preliminary work done by the SNAP:DRGN project in its first three months, and hearing from several potential project partners about their datasets, practices and reactions to our proposals. It was an extremely productive and positive affair, even when discussions sometimes became vigorous! I don’t mean to summarize all of the discussions and outcomes here (a series of blog posts by my colleagues over the next couple of weeks will do more of that), but I will share what I can of the presentations and slideshows that were shown at the workshop. Continue reading Workshop slides and recap


Last week, Faith gave a great overview of some of the issues involved in describing the relationships between people. This week, I’m going to come at the problem from the other side, looking at what data we have, and how SNAP plans to represent them.

Our initial datasets include Trismegistos People (TM, described by Mark), the Lexicon of Greek Personal Names (LGPN, described by Sebastian), and a set of names (article headwords) from the Prosopographia Imperii Romani, 2nd edition (PIR²) put together by Tom Elliott. TM has web pages that document the references to names and people found in papyri, many of which are hosted at, as well as resources describing the names and person; references, names, and persons all have unique identifiers. LGPN comes at the problem of modeling people from a different angle. They start with persons and add names and references; persons and names have unique identifiers. From PIR², we have only persons, with a “principal” name and identifying number (the article number) attached to them. Continue reading Tensions

Relationships Are Never Easy…

People are inherently social creatures. This means any project about people almost always has to deal with the relationships between people. In this, SNAP:DRGN is no exception. Since this is not a new problem there are a number of different models that already exist and are in use in other projects. Ideally we would reuse an existing, standard ontology to describe the relationships—this would allow us to be easily compatible with other similar projects that had (one hopes) gone through a similar thought process and came to the same conclusion. Continue reading Relationships Are Never Easy…