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Re: Concurrency in an RDB

From: Walt <wamitty_at_verizon.net>
Date: Fri, 29 Dec 2006 18:36:16 GMT
Message-ID: <Aedlh.79$c94.34@trndny09>

"Aloha Kakuikanu" <aloha.kakuikanu_at_yahoo.com> wrote in message news:1167362376.998197.210150_at_i12g2000cwa.googlegroups.com...
> Sampo Syreeni wrote:
> > Given the current, practical importance of both running text and the RM,
> > I wonder why a) there haven't been any genuine attempts at treating
> > strings, text and language in general in relational terms, or b) why the
> > RM folks won't confess it can't be done, given the current state of
> > knowledge, thereby acknowledging that there is data that just isn't
> > currently amenable to relational treatment.
>
> What "text" do you have in mind? A set of strings is formalized nicely
> as Kleene algebra. relational algebra is also Kleene algebra.
>
> Seriously, the parallels between Kleene algebra and relational algebra
> (in Codd's definition, not Tarski:-) are remarkable. If one accepts
> that join and union are the 2 fundamental operators of relational
> algebra, and agrees that Kleene star is somewhat less important
> operator, than both algebras hinge on join and union. The fundamental
> difference is that relational join is commutative, while Kleene's is
> not.
>

What's a good way to learn Kleene Algebra? Received on Fri Dec 29 2006 - 12:36:16 CST

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