From jcheney at inf.ed.ac.uk  Wed May  7 12:40:30 2008
From: jcheney at inf.ed.ac.uk (James Cheney)
Date: Wed, 07 May 2008 17:40:30 +0100
Subject: [POPLmark] Paper announcement: Mechanizing the Metatheory of LF
Message-ID: <1210178430.395.48.camel@oreb>

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From crary at cs.cmu.edu  Thu May  8 13:15:00 2008
From: crary at cs.cmu.edu (Karl Crary)
Date: Thu, 08 May 2008 13:15:00 -0400
Subject: [POPLmark] Paper announcement: Explicit Contexts in LF
Message-ID: <48233514.6040703@cs.cmu.edu>

I'm pleased to announce the available of a new paper on the explicit 
context method in Twelf, available at:

http://www.cs.cmu.edu/~crary/papers/

As always, comments and suggestions are welcome.

Karl Crary

-------------------

Explicit Contexts in LF

The standard methodology for representing deductive systems in LF
identifies the object's language's context with the LF context.
Consequently, any variable dealt with explicitly by any judgement or
metatheorem must be last in the context.  When the object language is
dependently typed, this can pose a problem for establishing some
metatheoretic results, since dependent hypotheses cannot be re-ordered
at will.

This paper presents a general technique that addresses such problems,
based on representing the object language's context as an explicit
object in LF while retaining the use of higher-order representation
for the object language's syntax.  A central result is that it is
possible to convert between explicit and implicit contexts, which
makes it feasible to use the standard methodology for most
developments, but use explicit contexts where necessary.  We do not
propose any extensions to LF; the technique can be utilized in
standard LF.


From vaughan2 at seas.upenn.edu  Thu May 29 17:53:35 2008
From: vaughan2 at seas.upenn.edu (Jeffrey Vaughan)
Date: Thu, 29 May 2008 17:53:35 -0400
Subject: [POPLmark] [Announcement] Cocorico and Coq-tips wiki Merger
Message-ID: <483F25DF.8090807@seas.upenn.edu>

Hi,

I'm pleased to announce that the Penn Coq-tips wiki has been merged into 
a newly reorganized Cocorico.  Please check us out at

  http://logical.futurs.inria.fr/cocorico/

--Jeff Vaughan