Re: compound propositions

From: Bob Badour <>
Date: Thu, 18 Mar 2010 19:39:23 -0300
Message-ID: <4ba2ab27$0$12425$>

paul c wrote:

> Bob Badour wrote:
> ...

>> I, too, find your use of the word sloppy, because a relation is a set 
>> of things that satisfy a predicate. The relation, itself, doesn't 
>> satisfy the predicate. Extent or extension is well-defined as a set of 
>> instances and describes what a relation is: a set of instances that 
>> satisfy a predicate.
>> ...

> Maybe, if it is possible to talk theory without ever talking
> implementation (which has its own conceptual, logical and physical
> 'levels'). Personally, if a relation has a header and the header
> satisfies a predicate,

Now you are using "satisfy" to mean something entirely different yet again.

> I have no problem with the statement that a
> relation satisfies a predicate, in the same way that if ISO/IEC
> publishes an IEC definition, I have no problem saying that ISO published
> it.

Neither headers nor relations satisfy predicates. A relation is the extent of some predicate. The tuples of a relation are the instances that satisfy the predicate. The header is a notational artefact of the formalism.

> I believe it is possible to "think outside of the box" without
> completely understanding or agreeing about the box as long as any
> resulting chaos is isolated to just a few people, although I have met
> people who don't think so (and some of them could never agree on the box
> in a hundred years). Exploration is often imprecise (not claiming to be
> much of an explorer myself nor that my musings have any importance
> except to a handful of fanatics here).

How successful an explorer would Columbus have been had he not been able to navigate from Genoa to Spain? Or locate his position relative to his origin?

> If it's of any help, I'll try to use single quotes more than I already
> do to help show when I suspect my usage is colloquial or might apply in
> to some context other than the one at hand.

Changing the symbol does not obviate the need to define it.

> I think I've exhausted my comments on vocabulary for today.
Received on Thu Mar 18 2010 - 23:39:23 CET

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