Re: compound propositions

From: Bob Badour <bbadour_at_pei.sympatico.ca>
Date: Thu, 18 Mar 2010 15:18:30 -0300
Message-ID: <4ba26e01$0$12455$9a566e8b_at_news.aliant.net>


paul c wrote:

> Bob Badour wrote:
>

>> paul c wrote:
>>
>>> David BL wrote:
>>> ...
>>>
>>>> This boolean valued function can be said to represent a
>>>> predicate under an interpretation but I'm not sure if that's what you
>>>> mean.  More specifically, what do you mean by "satisfy" when you say
>>>> relations satisfy predicates?
>>>> ...

>
> ...
>
>>> match the variable names apparent in the predicates and the attribute 
>>> types are applicable for whatever manipulations (eg., aggregation) 
>>> the predicate states.
>>
>>
>> In other words, the extension of a predicate is the set of all tuples 
>> that satisfy the predicate.
>> ...

>
> Yes, but David B asked what 'satisfy' means.

In that case, I suggest you not shy away from equality and boolean truth values. Unless you can think of a situation where "satisfy" means something other than "predicate evaluates to true". Received on Thu Mar 18 2010 - 19:18:30 CET

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