Re: deductive databases
Date: Tue, 17 May 2005 17:47:05 -0400
Message-ID: <z6adnWDcxurG-xffRVn-pw_at_comcast.com>
In-line:
"alex goldman" <hello_at_spamm.er> wrote in message
news:1301963.fDU1I1y9sr_at_yahoo.com...
> vc wrote:
>
>> Just to prevent spreading mis-information:
>>
>>> > alex goldman wrote:
>> [...skipped ...]
>>
>>>. First-order logic without functors is far less
>>> expressive.
>>
>> There is no FOL with 'functors'
>
> Looks like this idiot doesn't even realize the relation between Prolog and
> FOL. How much humiliation can he take?
>
> http://clip.dia.fi.upm.es/~logalg/slides/5_autded/node1.html
> http://www.cee.hw.ac.uk/~alison/ai3notes/subsection2_4_3_2.html
>
> Enjoy
>
>>>.First-order logic without functors is far less expressive. The
>>> restricted language is called Datalog. The inference in Datalog
>>> is decidable and the inference in First-order logic isn't.
>>
>> Datalog is decidable precisely because it chucked Prolog's 'functor'.
>> Prolog is of course undecidable.
>
> How does poorly rephrasing something count as prevention of spreading of
> mis-information (sic) ?
>
Well, the two web-sites <alex goldman>'s referring to are maintained by
folks clearly influenced by the Prolog jargon ("computational logic" and
"AI").
No standard mathematical logic handbook uses the word 'functor' as meaning a
'function symbol' for a very good reason.
In order to cure yourself from Internet "education" ill effects, you might
consider a trip to the nearest library and borrowing for example this book:
HB Enderton: A Mathematical Introduction to Logic, Academic Press, 1972