>John,
> Yes, it will be useful to agree on some term to refer to logical
>assertions implying existence of one entity dependent on existence of
>another. I usually hear those assertions referred to as simply
>"existentials" or "existential assertions" (01)
By who? That usage is incorrect. An existential
assertion is simply that something exists. What
you are talking about here are AE (forall-exists)
assertions: for every X there is a Y. (02)
>(or, in a database context, as
>"integrity constraints"). If there is no objection, we can use "functional
>dependency", but it would be nice to have a term that includes the word
>"existential" to emphasize the central importance of that logical symbol in
>the assertion. (03)
It is no more central than the universal. It is
exactly your emphasis on one of the two
quantifiers which is creating the confusion. Also
it need not be functional: that is the assertion
that for every X there is a *unique* Y. However,
if it is functional, then one need not even use
the existential quantifier, since the use of an
explicit function stands in its stead. (04)
> This may be one point of terminology work spilling some ink (or electrons)
>over.
> "existential functional dependency"??? (05)
Redundant. If its functional it must be
existential (in your sense). If you are seriously
worried about terminology, a good term for these
might be Skolem assertions. (06)
Pat (07)
>
>Pat
>
>Patrick Cassidy
>MICRA, Inc.
>908-561-3416
>cell: 908-565-4053
>cassidy@xxxxxxxxx
>
>
>> -----Original Message-----
>> From: ontolog-forum-bounces@xxxxxxxxxxxxxxxx [mailto:ontolog-forum-
>> bounces@xxxxxxxxxxxxxxxx] On Behalf Of John F. Sowa
>> Sent: Thursday, December 13, 2007 11:16 PM
>> To: [ontolog-forum]
>> Subject: Re: [ontolog-forum] brainwaves (WAS: to concept or not to
>> concept, is this a question?)
>>
>> Pat,
>>
>> That kind of connection is very common in databases and
>> knowledge bases. I agree that some way of describing it
>> clearly and simply would be useful.
>>
>> But I agree with Chris that using the term "existential
>> qualifier" is confusing. Some people use the term
>> "dependent entity", but that is also confusing, because
>> it would imply that any talk about a child would introduce
>> the two parents as "depedents".
>>
>> There is, however, a common term in database theory:
>>
>> functional dependency.
>>
>> In a relational database, for example, some columns of a table
>> might be "functionally dependent" on other columns. For an
>> employee relation, the columns for manager, department, and
>> salary are functionally dependent on the employee. That
>> means, for any employee x, there are functions f1, f2, f3,
>> such that
>>
>> f1(x) is the manager of x
>>
>> f2(x) is the department of x
>>
>> f3(x) is the salary of x
>>
>> I suggest that we use the term "functional dependency"
>> for such entities.
>>
>> John
>>
>>
>> _________________________________________________________________
>> Message Archives: http://ontolog.cim3.net/forum/ontolog-forum/
>> Subscribe/Config: http://ontolog.cim3.net/mailman/listinfo/ontolog-
>> forum/
>> Unsubscribe: mailto:ontolog-forum-leave@xxxxxxxxxxxxxxxx
>> Shared Files: http://ontolog.cim3.net/file/
>> Community Wiki: http://ontolog.cim3.net/wiki/
>> To Post: mailto:ontolog-forum@xxxxxxxxxxxxxxxx
>>
>
>
>_________________________________________________________________
>Message Archives: http://ontolog.cim3.net/forum/ontolog-forum/
>Subscribe/Config: http://ontolog.cim3.net/mailman/listinfo/ontolog-forum/
>Unsubscribe: mailto:ontolog-forum-leave@xxxxxxxxxxxxxxxx
>Shared Files: http://ontolog.cim3.net/file/
>Community Wiki: http://ontolog.cim3.net/wiki/
>To Post: mailto:ontolog-forum@xxxxxxxxxxxxxxxx
> (08)
--
---------------------------------------------------------------------
IHMC (850)434 8903 or (650)494 3973 home
40 South Alcaniz St. (850)202 4416 office
Pensacola (850)202 4440 fax
FL 32502 (850)291 0667 cell
phayesAT-SIGNihmc.us http://www.ihmc.us/users/phayes (09)
_________________________________________________________________
Message Archives: http://ontolog.cim3.net/forum/ontolog-forum/
Subscribe/Config: http://ontolog.cim3.net/mailman/listinfo/ontolog-forum/
Unsubscribe: mailto:ontolog-forum-leave@xxxxxxxxxxxxxxxx
Shared Files: http://ontolog.cim3.net/file/
Community Wiki: http://ontolog.cim3.net/wiki/
To Post: mailto:ontolog-forum@xxxxxxxxxxxxxxxx (010)
|