Re: SUPPORT FOR DECLARATIVE TRANSITION CONSTRAINTS

On Sep 26, 9:41 am, Bob Badour <bbad..._at_pei.sympatico.ca> wrote:
> Erwin wrote:
> > On 25 sep, 22:41, Brian <br..._at_selzer-software.com> wrote:
>
> >>The employee named paul c fills the position named toilet scrubber.
>
> >>Let's look at the information conveyed by this statement:
> >>1. there is an employee named 'paul c.'
> >>2. there is a position named 'toilet scrubber.'
> >>3. the named employee fills the named position.
>
> >>Now, suppose that paul c's position changes from toilet scrubber to
> >>floor sweeper.
>
> >>Assuming that no other proposition references an employee named paul c
> >>or a position named toilet scrubber, doesn't the denial of
>
> >>(a) The employee named paul c fills the position named toilet
> >>scrubber.
>
> >>also deny that there is an employee named paul c and that there is a
> >>position named toilet scrubber?
>
> > LOFL.
>
> > Who again was it that should go back to school and take a course in
> > logic ?
>
> > EXISTS employee : employee(name) = 'paul c' && employee(position) =
> > 'toilet scrubber'  does indeed imply EXISTS employee : employee(name)
> > = 'paul c' && EXISTS employee : employee(position) = 'toilet
> > scrubber'.  But note that the former and the latter are not
> > equivalent, since the former conveys the extra information that the
> > two properties apply to the very same person.
>
> > NOT EXISTS employee : employee(name) = 'paul c' && employee(position)
> > = 'toilet scrubber' ===
> > FORALL employee : NOT(employee(name) = 'paul c' && employee(position)
> > = 'toilet scrubber') ===
> > FORALL employee : employee(name) <> 'paul c'  OR  employee(position)
> > <> 'toilet scrubber')
>
> > The denial of "(a) The employee named paul c fills the position named
> > toilet scrubber." implies merely that if an employee is named paul c,
> > then he is not a toilet scrubber, and also that if an employee is a
> > toilet scrubber, then he is not named paul c.
>
> > So the answer to your question "doesn't the denial of ... also
> > imply ..." is, "No, doesn't.".
>
> In addition to Erwin's fine work, I will direct Brian to POOD, as
> distasteful as it might sound in the context of toilet scrubbers.- Hide quoted text -
>
> - Show quoted text -

How does the Principle of Orthogonal Design apply in this scenario? Received on Sun Sep 26 2010 - 19:55:54 CEST