RE: [discussion@2uworks.org] RE: [wg@2uworks.org] 3C + 2U = xP?



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From: Mitch Kokar (kokar@coe.neu.edu)
Date: Mon 09 Sep 2002 - 13:57:27 BST


Joaquin,

I think I can join the club - now I am confused. I am not sure whether my
interpretation of what you said is correct, but here is what I think about
denotations.

An element of a semantic domain is a *denotation* of an element of the
non-logical vocabulary. Conversely, an element of the non-logical vocabulary
*denotes* an element of the semantic domain.

If this is what you meant, then we agree and there is no confusion. But I'm
not sure.

==Mitch



> -----Original Message-----
> From: puml-list-request@cs.york.ac.uk
> [mailto:puml-list-request@cs.york.ac.uk]On Behalf Of Joaquin Miller
> Sent: Saturday, September 07, 2002 4:19 PM
> To: Tony Simons
> Cc: puml-list@cs.york.ac.uk; wg@2uworks.org; discussion@2uworks.org
> Subject: RE: [discussion@2uworks.org] RE: [wg@2uworks.org] 3C + 2U = xP?
>
>
> That does help, Tony, very much so.  Thanks.
>
> I had not realized that 'to denote' was also used to mean 'to be the
> interpretation of.'  I suppose that's because of my distinction
> between the
> range of the interpretation function of formal semantics and the system
> that the model represents; and because i took 'to denote' in its ordinary
> dictionary meaning (e.g. Cambridge Dictionary of Philosophy).  As
> a result
> of that distinction and that meaning, i would expect 'to denote'
> to be used
> with respect to the relation of a model element to what that element
> represents, not the relation of that element to something in an
> interpretation (model) of that model (theory).  So i had it all backwards.
>
> Probably best to avoid the jargon of the formal semantics trade in the 2U
> documents.  That's not your problem, or puml's.  I'll suggest it to 2U.
>
> It is reassuring to see we share the idea that there are three things,
> model (theory), system, and interpretation (model).  And at least two
> essential relations, representation and interpretation (or, as
> used in the
> text, denotation).
>
> Here is where we part company:
>
> >-- well, the meaning of the concepts-as-UML-elements is given in the
> >semantic domain;  the meaning of the real world/system is more tricky!
>
> i would say the meaning of the model elements is found in the system.
> and that the system has no meaning.
> (Sure, some things do have meaning.  If statues of the leader are erected
> in the squares, the statues have a meaning.)
>
> that's because i feel the distinction between meaning and formal
> semantics
> is central to keeping everything straight.  (and, since experts
> tend to use
> 'semantics' to mean formal semantics: i feel the distinction between
> meaning and semantics is central to keeping everything straight.)
>
> the (set-theoretic) semantics of a model element might be some
> set, but the
> model element does not mean some set, it means a certain item in
> the system.
>
> or, if we don't want to use 'to mean' in that way, then the appearance of
> an element in a model does not mean there is a certain set, it
> means there
> is to be a certain item in the system.
>
> but that is just to explain my frequent confusion.  i don't mean
> to suggest
> changes to the technical language used by experts.  i know that 'x means'
> is often used by experts to mean the image of x under the
> interpretation is.
>
> Again, thanks for the careful elucidation.
>
>
> At 10:17 AM 9/7/2002, Tony Simons wrote:
> >Hi again,
> >
> >Joaquin Miller wrote:
> >
> >=====
> > > > >A consequence of the semantic domain design principles is that the
> > > > >semantic domain should not contain equivalences; i.e. all semantic
> > > > >elements denote distinct concepts.
> >
> >One possible reading:
> >    semantic elements are the items in the semantic domain
> >    the items in the semantic domain denote concepts
> >=====
> >
> >Well I can't really comment on the wording of the 2U document, but I
> >I read this as meaning that each element in the semantic domain is
> >unique (not equivalent to any other in the domain) and therefore a
> >denotation of a distinct element from the UML model.  I don't think
> >that there's meant to be another level of concepts below the semantic
> >domain, which somehow explains that domain.  Granted, the wording does
> >seem a bit fluffy.
> >
> >It would have been easier to say:  "Because of the way the semantic
> >domain is constructed, elements in the domain are unique.  No element
> >is equivalent to any other."
> >
> >This would have avoided introducing "concepts" which seems to be the
> >source of the confusion.  I haven't seen the full context of the above
> >statement, but the "concepts" may refer to UML model elements, in which
> >case I would read this as meaning: "if two model elements are denoted
> >by different semantic elements, then they are distinct".
> >
> >My preferred answers to your questions are therefore:
> >
> > >  Which are the concepts that the items in the semantic domain (the
> > > "semantic elements") denote?
> >
> >-- elements from the semantic domain are the denotations (interpretation)
> >    of UML model elements;  it is reasonable to say that they "denote the
> >    concepts" (from the model layer above)
> >
> > >  Where are those concepts found?
> >
> >-- these "concepts" are just ordinary elements of UML models, whose
> >    meaning is given by the mapping to elements in the semantic domain
> >
> > >  What do those concepts denote?
> >
> >-- probably not a well-formed question; they model some aspect of the
> >    software system under consideration, but "denoting" may be the
> >    wrong term, since the relationship is one of abstraction rather
> >    than precise characterisation.
> >
> > >  Where do we find the meaning of those concepts?
> >
> >-- well, the meaning of the concepts-as-UML-elements is given in the
> >    semantic domain;  the meaning of the real world/system is more
> >    tricky!
> >
> >I hope this helps,
> >
> >--Tony
> >
> >=================================================================
> =========
> >
> >Dr Anthony J H Simons                   a.simons@dcs.shef.ac.uk
> >Senior Lecturer in Computer Science     http://www.dcs.shef.ac.uk/~ajhs
> >Director of Teaching
> >
> >Department of Computer Science          tel:  (+44) 114 22 21838
> >University of Sheffield                 dept: (+44) 114 22 21800
> >Regent Court, 211 Portobello Street     fax:  (+44) 114 22 21810
> >SHEFFIELD, S1 4DP                       univ: (+44) 114 22 22000
> >United Kingdom
> >
> >=================================================================
> =========
>
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