Re: Urgent! Semantic question about rdfs:domain.

From: Lynn Andrea Stein (
Date: 04/25/01

This was the subject of some discussion within the pre-DAML RDF community as
well.  I believe that what was settled on, for RDF, at least, was what you call
"restriction from above" for both domain and range.  I thought some statement to
this effect was going to be made.  On the other hand, RDF/S as originally written
clearly says restriction from below on domain.

Perhaps Ralph remembers this round?


pat hayes wrote:

> Checking thru the walk-thru.  The section which introduces properties
> is worded in a way that suggests a different semantics from the one
> given in the model theory.
> The example says that the domain of hasParent is #Animal, and this
> clearly suggests that the intention is that this should mean that
> every animal has a parent, ie that hasParent applies to the entire
> domain class (in contrast to the range specification.) I wrote the
> following 'explanation' before realising that it might not be true:
> "The range specification restricts the property from 'above', ie it
> specifies a class into which the value of the property must fit,
> while the domain restricts it from 'below', ie it specifies a class
> which must be included in the class of things that the property can
> be applied to. "
> Is this correct??  Because if so, the semantics is wrong at this point. It says
> <rdfs:domain,?P,?C>    means:    if <x,y> in IR(?P) then x in IC(?C)
> but if the above is correct then it ought to say:
> <rdfs:domain,?P,?C>    means:   if x in IC(?C) then for some y, <x,y> in IR(?P)
> If the semantics is correct, however, then the example in the
> walkthrough is rather misleading, and we will need to correct against
> any potential misunderstanding. Also, in this case, HOW does someone
> give a 'lower' bound to the domain of a property? Eg how can one say
> that hasParent applies to *any* animal? (If both domain and range
> restrict from above, then it would be consistent to give all
> properties empty domains and ranges.)
> I await clarification from the Semantic Gurus, and will write
> appropriate prose for the walkthru when clarity is restored to my
> mind.
> Pat Hayes
> PS. A related question. If
>     <rdfs:domain,?P,?D>
>     <rdfs:range,?P,?R>
>     <inverseOf,?P,?S>
> does it follow that
>     <rdfs:domain, ?S,?R>
>     <rdfs:range,?S,?D>
> ??
> PPS. The only way to really learn something is to try teaching it to
> other people :-)
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