Re: compound propositions
From: paul c <toledobythesea_at_oohay.ac>
Date: Mon, 15 Mar 2010 23:01:16 GMT
Message-ID: <0%ynn.68205$Db2.48582_at_edtnps83>
>
> No, I meant the internal predicate but I screwed up in any case. I meant
> to use union not join. Sadly, you removed all reference to the original
> context.
> ...
Date: Mon, 15 Mar 2010 23:01:16 GMT
Message-ID: <0%ynn.68205$Db2.48582_at_edtnps83>
Bob Badour wrote:
> paul c wrote:
>> Bob Badour wrote: >> ... >> >>> What is the predicate of Customer[id] join Client[id] where [] >>> signifies project? ... >> >> If you mean what is the 'external' predicate, I can't say,
>
> No, I meant the internal predicate but I screwed up in any case. I meant
> to use union not join. Sadly, you removed all reference to the original
> context.
> ...
But are you saying there is a relevant difference between the recording of a compound proposition that involves join and one with union? (given that practical union values are so-called 'union-compatible')
I realize that it's unlikely both would be satisfied by the same value but as far as whether either records the connective is concerned I can't see any difference, sames goes for projection. (also realize, based on people I've known, that some might consider my questions childish, but I don't care! Maybe I've just been getting away with something for all these years, thinking that relational closure means no compound propositions.) Received on Tue Mar 16 2010 - 00:01:16 CET