# Re: pls help me grok ELF, basis of PCA

From: Dan Connolly <connolly@w3.org>
Date: Wed, 19 Apr 2000 01:53:36 -0500
Message-ID: <38FD57F0.C39367C9@w3.org>
To: sw99@w3.org
Thanks to a little help from my friends, I managed to
get past this bump and thru section 2.2 of the paper...

see
http://www.w3.org/XML/9711theory/ELF.lsl
Id: ELF.lsl,v 1.5 2000/04/19 06:41:36 connolly Exp \$

or the hypertext version
http://www.w3.org/XML/9711theory/ELF.html
aka
http://www.w3.org/XML/9711theory/ELF

Dan Connolly wrote:
>
> So this PCA stuff
>         http://www.cs.princeton.edu/sip/projects/pca/
>
> is based on this ELF thing
>         http://www.dcs.ed.ac.uk/lfcsreps/91/ECS-LFCS-91-162/
>
> So I'm trying to read the ELF paper. I can't parse the formulas.
> In partuclar, the B-KIND-SIG rule on page 7... second premise.
> It seems to say
>
>         K is a kind in \sigma
>
> but this doesn't match any of the assertion forms on the previous page:
>
>         \sigma is a valid signature
>         \gamma is a valid context in \sigma
>         K is a kind in \gamma and \sigma
>         A has kind K in \gamma and \sigma
>         M has type A in \gamma and \sigma
>
> Help? Do they imply an empty \gamma in their notation or something?

--
Dan Connolly, W3C http://www.w3.org/People/Connolly/

Received on Wednesday, 19 April 2000 02:53:52 UTC

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