Re: a or b or both - mystery..

[Murali Mani <mani@CS.UCLA.EDU>]

Thinking a little bit more --
I think we all have been taught systems which are closed, with or without
our realization.
I think closure to me implies that an operation is defined -- i am
seriously yet to see union of XML Schemas defined anywhere.
Also closure implies the tightest possible output schema, tightness is
desirable if you can get it easily -- I think that is what regular tree
languages provide.

But these are things to be discussed with experts. I did try to bring up
slightly this issue with the XML Schema WG sometime in Dec '00 -- I think
they might very well be aware of these issues.

<warning>speaking for himself only</warning>

regards - murali.

On Tue, 17 Apr 2001, Murali Mani wrote:

>
> I read Joe English's mail also.
> Let me ask you -- is there a definition of union of XML Schemas. I want to
> take union of 2 XML schemas, show me a way of doing it.
>
> For every operation, we should define how we can obtain the output type --
> this is not needed unless your processing uses Schema.
>
> I am slightly sceptical that we will be able to define any meaningful
> union or other operations for XML Schemas.
>
> <warning>speaking for himself only</warning>
>
> cheers - murali.
>
> On Tue, 17 Apr 2001, Marcus Carr wrote:
>
> >
> > Murali Mani wrote:
> >
> > > I have asked professors and others -- everyone I have asked believes
> > > things just will not work without closure - you will get unexpected
> > > things.
> >
> > What things will not work and what unexpected things might you get?
> >
> > > I think if you use XML only for data exchange, then closure does
> > > not matter, but if you want to do actual processing, then I think closure
> > > is *very* important.
> >
> > What sort of processing? I have been involved with (perhaps a different form of?) SGML
> > and XML processing for ten years and I don't really even understand the problem...:-)
> >
> > > And it was a pleasure trying to explain whatever I know. I think everyone
> > > in this group tries to learn from the other.
> >
> > Absolutely - what you know still seems to be whizzing by me a bit, but I appreciate
> > your taking the time.
> >
> >
> > --
> > Regards,
> >
> > Marcus Carr                      email:  mrc@allette.com.au
> > ___________________________________________________________________
> > Allette Systems (Australia)      www:    http://www.allette.com.au
> > ___________________________________________________________________
> > "Everything should be made as simple as possible, but not simpler."
> >        - Einstein
> >
> >
> >
>
>
>
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