# Re: General semantics

From: Nilone <reaanb_at_gmail.com>

Date: Fri, 21 May 2010 05:35:28 -0700 (PDT)

Message-ID: <c8ecbb1d-3127-4bff-ad95-8c3179d8a9fd_at_z15g2000prh.googlegroups.com>

On May 21, 1:38 pm, Erwin <e.sm..._at_myonline.be> wrote:

Date: Fri, 21 May 2010 05:35:28 -0700 (PDT)

Message-ID: <c8ecbb1d-3127-4bff-ad95-8c3179d8a9fd_at_z15g2000prh.googlegroups.com>

On May 21, 1:38 pm, Erwin <e.sm..._at_myonline.be> wrote:

*> On 21 mei, 12:45, Nilone <rea..._at_gmail.com> wrote:**>**> > On May 21, 7:57 am, Clifford Heath <n..._at_spam.please.net> wrote:**>**> > > paul c wrote:**> > > > By unary relation I mean a relation with one attribute (which I think is**> > > > pretty standard lingo, surprised that anybody here wouldn't think that)**>**> > > Right, that's what I thought you meant. In which case, it could be a**> > > representation of either an existential fact type (an object type),**> > > or a unary predicate over one. The distinction is important. A unary**> > > predicate creates a subset of the object type it involves.**>**> > > This distinction was, I believe, the cause of your earlier disagreement.**>**> > > Further, a unary fact type does not have to be mapped as a unary relation.**> > > It could be represented as a boolean value in a table of that object type.**>**> > > > but I have no idea what a 'fact type' is. I know of relation and tuple**> > > > types but don't know what use terms like 'fact type' or 'unary fact'**> > > > terms might have.**>**> > Perhaps, fact type = intension while unary fact = proposition**>**> Instantiating a predicate with attribute values always yields a**> proposition, no matter what the degree of the relation is.*Thanks for the correction. Let me try again: it seemed to me that Clifford's unary fact types correspond to propositional functions, while his unary facts correspond to the propositions yielded by instantiating such a type. As such, I see no real argument between the models; in fact, the little I know of ORM (mostly from looking at Halpin's page a while back) seemed to match up with the relational model well. Received on Fri May 21 2010 - 07:35:28 CDT