Re: Relational lattice
From: Jan Hidders <jan.hidders_at_REMOVETHIS.pandora.be>
Date: Fri, 11 Mar 2005 18:13:02 GMT
Message-ID: <OclYd.35394$Ai.3302500_at_phobos.telenet-ops.be>
>
> Good question. Very good question. I suspect not, but I'm not sure and
> certainly have no proof. I do know that you can if you use the nested
> relational algebra.
>
> By the way, I just ran into a somewhat related paper. It's probably not
> exactly what you are looking for, but you might be interested in it:
>
> "Solving equations in the relational algebra"
>
> http://arxiv.org/abs/cs.LO/0106034
Date: Fri, 11 Mar 2005 18:13:02 GMT
Message-ID: <OclYd.35394$Ai.3302500_at_phobos.telenet-ops.be>
Jan Hidders wrote:
> Vadim Tropashko wrote:
>> >> Is it possible to express transitive closure in a finite set of >> equations as well?
>
> Good question. Very good question. I suspect not, but I'm not sure and
> certainly have no proof. I do know that you can if you use the nested
> relational algebra.
>
> By the way, I just ran into a somewhat related paper. It's probably not
> exactly what you are looking for, but you might be interested in it:
>
> "Solving equations in the relational algebra"
>
> http://arxiv.org/abs/cs.LO/0106034
http://www.cse.ucsc.edu/~kolaitis/
- Jan Hidders