Re: Definitions and provenance and invariance

Hi Graham,

In the world of ontologies, it is the simple, small ontologies that say very
> little, and leave little room for disagreement, that are widely used (FOAF,
> SiOC, DC, VOID, etc.).
>

That is completely true, and that is why I like your proposal, because it is
simple and easily understandable. I also like the notion of "wraping" the
provenance statements around a Provenance resource, because this way you can
describe them with provenance too. From my point of view, if the core of the
PIL is simple, it will be widely adopted.

Best,
Daniel

2011/6/14 Graham Klyne <GK@ninebynine.org>

> I'm getting a distinct feeling that the reductionist focus on trying to
> define terms in isolation is not helping us move towards a useful consensus.
>  I feel it is tending to force our attention to matters that are not
> important and where we might reasonably have different views, rather than on
> those matters where we already are pretty much agreed. I'll try and explain
> why, then I'll offer a an alternative approach.
>
>
> The problem:
>
> The more precisely one tries to define a concept, the more there is in the
> definition to disagree with, or the fewer real-world entities actually
> conform to that definition.  In model theoretic formalisms, one can never
> completely constrain the definition of a term to limit the satisfying
> interpretations to just one possible referent for that term (cf. "The chief
> utility of a formal semantic theory is not to provide any deep analysis of
> the nature of the things being described by the language [...] but rather to
> provide a technical way to determine when inference processes are valid" --
> Pat Hayes, RDF Model Theory, http://www.w3.org/TR/rdf-mt/).
>
> In the world of ontologies, it is the simple, small ontologies that say
> very little, and leave little room for disagreement, that are widely used
> (FOAF, SiOC, DC, VOID, etc.).  (There are exceptions, such as the Gene
> Ontology family, but the difference here is that such ontologies are being
> used within a community to encode a substantial body of evolving domain
> knowledge.)
>
> In natural language (which we are are using to create our definitions), W V
> O Quine compellingly argues (in at least one of his essays in "Ontological
> Relativity") that it is not possible to constrain meanings for individual
> terms in ways that allow for correct assessment of the truth of any
> sentence, and that the role of words does not necessarily map one-to-one
> between languages that have comparable expressive power (Quine describes the
> role of number words in western languages and Japanese).  But what we can do
> more easily is agree (or not) about the truth of complete sentences.  (As I
> write this, I don't have my copy of Ontological Relativity to hand, so am
> relying on memory for the references.)
>
>
> Proposal:
>
> What I propose, and I think it parallels a thought that Jim has already
> expressed (
> http://lists.w3.org/Archives/Public/public-prov-wg/2011Jun/0015.html, and
> elsewhere), is that we look at a minimal model of related provenance
> concepts, and agree something about the combined meanings of the concepts
> and their relationships.  For the purposes of exposition, I shall focus on
> time-varying properties, but I believe the approach can generalize to any
> variation in a resource's property.
>
> My core structure is:
>
>  Dynamic resource
>    |
>    v has view
>    |
>  View resource
>    |
>    v has provenance
>    |
>  Provenance resource
>
> Where the possible sets of differently labelled resources are not disjoint.
>  I think the key criterion that we are trying to express is that the
> relation has provenance carries a requirement of invariance between the view
> resource and the provenance resource.
>
> Suppose that the "Dynamic resource has a number of different observable
> properties, some of which do not change over time, and others which do.
>  Then the View resource would be a resource for with a similar set of
> properties such that do not change over time, but correspond to the dynamic
> resource properties at a given time (including properties that do not change
> over time).  If the Dynamic resource does not change over time, then it may
> also serve as its own view resource:  the has view property can be
> reflexive.
>
> The provenance resource is an assertion about the properties of the view
> resource.  I believe the key requirement that we try to capture is that the
> properties about which the provenance resource makes assertions are
> invariant - there is no assertion in the provenance resource which is not
> always true of the view resource.
>
> ...
>
> This could (and should) be cast in more mathematical terms (e.g. resource
> properties as functions of time t), but I think it would be quite easy to
> formally express the required constraints and I'll skip doing so in this
> email.
>
> In writing this, I think it reflects quite closely what Luc has been
> describing through IVPTs, or whatever, but in in considering the different
> resources and relationships between them I find it much easier to focus on
> and express what (I think) is important.
>
> #g
> --
>
>
>