Re: Guessing?
From: paul c <toledobysea_at_ac.ooyah>
Date: Tue, 08 Jul 2008 22:07:41 GMT
Message-ID: <NyRck.65245$Jx.43062_at_pd7urf1no>
>
> Correctly formed, each extension of the database would consist of two
> relations: one for mechanical engineers and one for electrical engineers.
> There are three possible extensions:
>
> one where Susan is both an electrical engineer and a mechanical engineer,
>
> MechanicalEngineers {{Person:Susan}}
> ElectricalEngineers {{Person:Susan}};
> ...
Date: Tue, 08 Jul 2008 22:07:41 GMT
Message-ID: <NyRck.65245$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? Received on Wed Jul 09 2008 - 00:07:41 CEST