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On 9/13/13 5:51 AM, Esmé Cowles wrote: > Thomas- > > This isn't something I've run across yet. But one thing you could do is create some URIs for different kinds of unknown/nonexistent titles: > > example:book1 dc:title example:unknownTitle > example:book2 dc:title example:noTitle > etc. I'm bothered by the semantics of this... but maybe I'm being too rigid. This states that the title is a URI, not a string, and that the URI is a status, not the actual title. Your system will have a mixture of literal strings that ARE titles and URIs that say something about titles, both as objects of dc:title. The object of DC title needs to be the title. The title COULD be a URI if the URI represents the title (e.g. a uniform title in an authority file). Even if this turns out to be "legal" from an RDF point of view, it seems that this would complicate title displays because you'd have to treat these URIs differently from the usual title literals, which you could just grab and toss into a display. I'd probably leave title as the literal string, and create a new property for title status that takes its value from a controlled list. In fact, wouldn't we need something almost identical for anonymous works, to say that there really isn't an author. (Cataloging knowledge lapse: we quit using "Anonymous" as an author a while ago, right?) Given the open world assumption, we are going to need to make these kinds of negative statements. Also, remember that OWL does NOT constrain your data, it constrains only the inferences that you can make about your data. OWL operates at the ontology level, not the data level. (The OWL 2 documentation makes this more clear, in my reading of it. I agree that the example you cite sure looks like a constraint on the data... it's very confusing.) > > > > > > > > > > This book has no title: > example:thisbook dc:title hasobject:false . I don't think the title itself can be "hasobject:false". I think you need to have a property like: xx:hasATitle and this can be true or false. But I'm going to run this by the folks who developed dc in RDF and see what they say. [Did so, they concur = value of title must be a title, not information about title or status of title.] Note that dcterms title is defined specifically as having a literal value: Term Name: title URI: http://purl.org/dc/terms/title Label: Title Definition: A name given to the resource. Type of Term: Property <http://www.w3.org/1999/02/22-rdf-syntax-ns#Property> Refines: http://purl.org/dc/elements/1.1/title Version: http://dublincore.org/usage/terms/history/#titleT-002 Has Range: http://www.w3.org/2000/01/rdf-schema#Literal Whereas dc 1.1 (the old 15 element set) is more open: URI: http://purl.org/dc/elements/1.1/title Label: Title Definition: A name given to the resource. Type of Term: Property <http://www.w3.org/1999/02/22-rdf-syntax-ns#Property> Version: http://dublincore.org/usage/terms/history/#title-006 Note: A second property with the same name as this property has been declared in the dcterms: namespace (http://purl.org/dc/terms/). See the Introduction to the document "DCMI Metadata Terms" (http://dublincore.org/documents/dcmi-terms/) for an explanation. I still think you are going outside of the definition of dc:title, which is "The name of the resource." UNLESS you treat your "no title" as the actual name of the resource, like "untitled" as the title of a painting. But then we do have a serial with the actual title "Title varies" ... ;-) kc > > It is unknown if this book has a title (sounds undesirable but I can think of instances where it might be handy[2]): > example:thisbook dc:title hasobject:unknown . > > This book has a title but it has not been specified: > example:thisbook dc:title hasobject:true . > > In terms of cataloguing, the answer is perhaps to refer to the rules (which would normally mandate supplied titles in square brackets and so forth) rather than use RDF to express this kind of thing, although the rules differ depending on the part of description and, in the case of the kind of thing that prompted the question- the presence of clasps on rare books- there are no rules. I wonder if anyone has any more wisdom on this. > > Many thanks, > > Tom > > [1] Adapted from http://www.w3.org/2007/OWL/wiki/Primer#Object_Properties > [2] No many tbh, but e.g. title in an unknown script or indecipherable hand. > > --- > > Thomas Meehan > Head of Current Cataloguing > Library Services > University College London > Gower Street > London WC1E 6BT > > [log in to unmask] -- Karen Coyle [log in to unmask] http://kcoyle.net ph: 1-510-540-7596 m: 1-510-435-8234 skype: kcoylenet