Re: General semantics

"Erwin" <e.smout_at_myonline.be> wrote in message news:4df4d884-e6bb-427e-b97b-96647f171a11_at_m33g2000vbi.googlegroups.com... On 25 mei, 23:04, "Mr. Scott" <do_not_re..._at_noone.com> wrote:
> "paul c" <toledobythe..._at_oohay.ac> wrote in message
>
> news:YodKn.4587$Z6.2983_at_edtnps82...
>
>
>
>
>
> > Mr. Scott wrote:
> > ...
>
> It is my understanding that an OID is a system-generated name that is
> assigned to an object, and that each OID is assigned to only one object.
> In
> the OO world, OIDs are only assigned to instances of reference types.
> Maybe
> that's why D&D erroneously call them pointers.

<<QUOTE
A reference type has the property of being a (set of all possible) reference(s), and nothing more than that.
>>QUOTE
DISAGREE: a reference type is any type that is not a value type.

<snip>

> Suppose that you have a relation that records what you have in the
> cupboard,

<<QUOTE
Relations don't record anything. Relation _variables_ do. Speak precisely or shut up.
>>QUOTE
A relation is what has been recorded, so there is nothing wrong with referring to what it records.

> {item, quantity}.
> What is the difference between the following relations (assuming the
> closed
> world assumption of course)?
>
> {{item:"can of dog food", qty:3},{item:"can of cat food", qty:0}}
>
> {{item:"can of dog food", qty:3}}
>
> Both indicate that there are three cans of dog food, but does the second
> indicate that there is no such thing as a can of cat food, or is it
> synonymous with the first?

<<QUOTE
Well, if you do not provide the exact predicate of the relation _VARIABLES_ that you have in mind, then it would be pretty hard to tell for anyone whether propositions derived from them are synonymous or not, no ?
>>QUOTE
It doesn't matter what the predicate is because the propositions in question differ in form:

Pab /\ Pcd /\ ~(Pad \/ Pcb)

Pab /\ ~(Pad \/ Pcb \/ Pcd)

These are clearly NOT the same.

> Under the closed world assumption, the
> proposition that is the result of substituting the values "can of cat
> food"
> and 0 for the variables in the predicate for the second relation is
> supposed
> to be false because the tuple doesn't appear in the relation!

<<QUOTE
You claim that without giving the precise predicate that you have in mind.
>>QUOTE
As I stated earlier, it doesn't matter what the predicate is. The form of the proposition that is a consequence of applying the closed world interpretation is different in each case regardless of what the actual predicate is.

<<QUOTE
If the predicate is "The shop sells product <x> and the current quantity available is <y>", then it makes PERFECT SENSE for a tuple {"can of cat food", 0} to appear in that relation _VARIABLE_.
>>QUOTE
But there is the contradiction. It doesn't appear in the second relation but the absence of it logically implies it: that doesn't make any sense. Received on Wed May 26 2010 - 03:46:07 CEST