Re: deductive databases

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 Received on Wed May 18 2005 - 06:00:39 CEST