Re: Guessing?

From: paul c <toledobysea_at_ac.ooyah>
Date: Tue, 08 Jul 2008 23:42:14 GMT
Message-ID: <qXSck.59540$kx.32045_at_pd7urf3no>

Brian Selzer wrote:

> "paul c" <toledobysea_at_ac.ooyah> wrote in message 
> news:NyRck.65245$Jx.43062_at_pd7urf1no...
>> Brian Selzer wrote:

>>> "paul c" <toledobysea_at_ac.ooyah> wrote in message
>>> news:33Ock.59297$kx.264_at_pd7urf3no...

>>>>> Brian Selzer wrote:
>>>>> ...
>>>>>> Consider the following statements:
>>>>>>
>>>>>> 1. Susan is an electrical engineer.
>>>>>> 2. Susan is a mechanical engineer.
>>>>>> 3. Susan is an electrical engineer or Susan is a mechanical engineer.
>>>>>> ...
>>>> I have another question.  Suppose we have a database that involves only 
>>>> statement 3.  Just what does its extension look like?
>>>>

>>> Correctly formed, each extension of the database would consist of two
>>> relations: one for mechanical engineers and one for electrical engineers.
>>> There are three possible extensions:

>>>

>>> one where Susan is both an electrical engineer and a mechanical engineer,

>>>

>>> MechanicalEngineers {{Person:Susan}}
>>> ElectricalEngineers {{Person:Susan}};
>>> ...

>> Okay, now stop right there.  (It is the case you originally gave, ie., 
>> statements 1 and 2 are both true.)  What is the extension of 'statement' 
>> 3?
> 
> You've lost me.  When did I say that statements 1 and 2 are both true? 
> IIRC, I wrote, "consider the following statements:"
> 
> 

I see this snippet from June 22:

"It is only the fact that the value that maps to Susan appears also in both of the base relations that tells us that in fact Susan is both an electrical engineer and a mechanical engineer." Received on Wed Jul 09 2008 - 01:42:14 CEST