Re: deductive databases

From: alex goldman <hello_at_spamm.er>
Date: Wed, 18 May 2005 09:23:32 -0700
Message-ID: <13164077.iA2d7LS8ze@yahoo.com>

VC wrote:

> 
> "alex goldman" <hello_at_spamm.er> wrote in message
> news:2040780.qLjtXq1iaR_at_yahoo.com...

>> You just keep inventing brand-new silliness, as if what you previously
>> wrote
>> isn't enough?
>>
>> VC wrote:
>>
>>> -- that FOL can get rid of function symbols and be as expressive as with
>>> them;
>>
>> ?!?
>>
>>
>> First-order logic without function symbols (F O) provided the basis for
>> query languages for the early commercial relational database systems. Its
>> appeal lies in its simplicity, clear semantics, and dual declarative and
>> procedural incarnations. Indeed, F O has a simple algebraization which is
>> particularly amenable to optimization. While F O has many appealing
>> features, it has limited expressive power. For instance, it cannot
>> compute the transitive closure of a graph. [1]
>>
>> [1] Expressive Power of Query Languages, Serge Abiteboul & Victor Vianu
>>
>>

http:www.informatik.uni-freiburg.de/~dbis/lehre/db-th-ws0001/papers/abi_vianu.ps

> 
> 1. It's been know , at least since Russel's times, that any FOL formula
> with function symbols
> can be translated to an equivalent FOL formula without function symbols.
> The Horn subset however cannot.
> 
> 2. Are you familiar with the notion of "argumentum ad verecundiam " ?

Let me get this straight. Because you don't grasp the fundamentals, I have to reproduce all theories, proofs, etc. right here, without referencing any papers by others? I have never seen such idiocy. (Actually, HERC comes to mind, but he has a medical condition)

You wrote: "FOL can get rid of function symbols and be as expressive as with them"

Abiteboul & Vianu write: "[FOL without function symbols] has limited expressive power. For instance, it cannot compute the transitive closure of a graph"

How more explicit do you need the proof that you don't know what the hell you are talking about? (Rhetoric question, you are just a troll, after all) Received on Wed May 18 2005 - 11:23:32 CDT