

From: PJOHNSON@Wesleyan.bitnet
Subject: Dense frame maps

I need the help of a frame theorist in the following problem:  Under what
assumptions is a dense morphism of frames f:A -> B , actually one to one?

I define such a map f to be dense, just in case f(a) = 0 implies a = 0.
(Maybe this is the start of my trouble).  Then an argument occurs to me
that I know must be incorrect, but I just can't get out of my mind:
(In what follows, let < stand of less than or equal, and for and element
x of a frame A let -x be the largest element of A which is disjoint from
x.)
Claim:  If A is regular and f:A -> B is dense, then it is one to one.
The assumptions seems to imply that x is well below y in A  iff f(x) is
well below f(y) in B.  Then, since A is regular, two elements are different
just in case one has something well below it that is not well below the
other.  Can someone lend a hand?



From:       Paul Taylor <pt@doc.ic.ac.uk>
Date:       Tue, 14 Aug 90 13:54:01 BST
Subject:    commutative diagrams

*** DISTRIBUTION ***
I dispatched copies of the commutative diagrams package to all those who
requested it on about 20 July. The North American distribution was handled
by an IC student currently working on the Athena project at MIT, whilst
I sent to European and other users myself.  Unfortunately, there appear
to have been problems with both dispatches.  Please, therefore, would you
contact me if you are using / want to use the package, saying * You've got it,
* you asked for it but didnt get it or * You didnt ask for it but want it.
Where several people at an institution use it (Cambridge, Cornell, Edinburgh,
Glasgow, MIT, Oxford & Stanford) it would help also if one one them could
be designated "local manager". I would also appreciate a volonteer who
is competent with TeX, Unix & email at a .edu site to handle forwarding of
future releases to N.American users. Thanks.

*** DISCUSSION POINT ***
One person complained at being asked to acknowledge me in his published papers.
TeX & LaTeX are now standard and indispensible tools, so we should credit
Knuth & Lamport. What do you think are the pros & cons of such acknowledgement?

Date: Wed, 15 Aug 90 11:31:36 EDT
Subject: Re: commutative diagrams formatting package
From: pratt@cs.stanford.edu

Date: 14 Aug 90 14:13:10 PDT (Tue)

 *** DISCUSSION POINT ***
 One person complained at being asked to acknowledge me in his
 published papers.  TeX & LaTeX are now standard and
 indispensible tools, so we should credit Knuth & Lamport. What
 do you think are the pros & cons of such acknowledgement?

(Since types@theory readers are presumably Paul's main customers I
guess that makes this the right forum for this discussion.)

Thus far I've simply been putting "The paper was typeset using D.
Knuth's TeX, L. Lamport's LaTeX macros, and P. Taylor's diagram macros"
in my acknowledgment sections.  But Paul's bringing this issue up here
got me to thinking again about it.  Is this *enough* acknowledgment?

Shifting to more credits in publishing is a nice idea provided people
aren't left out unfairly.  Traditionally the movie industry has been as
long on infrastructure credit as the publishing industry has been
short.  Both have large amounts of such infrastructure, which for
fairness calls for a lot of credits, if any, in either business.

In today's electronic publishing, certainly Knuth and Lamport spring to
mind immediately.  But if you use Unix you should also credit Ritchie
and Thompson, if vi or Emacs then Bill Joy or Richard Stallman, if a
Sun then various hardware and software designer-implementors, including
me for drawing your every pixel via Pixrect---I put a lot of work into
making the Pixrect graphics interface design clean without unduly
compromising performance of the implementation, so that the screen
wouldn't be a bottleneck for your text editor or figure editor.

One might use "volunteer labor" as a criterion for limiting the list of
credits.  But what exactly constitutes a volunteer?  And do you want to
send the message that work we enjoy should be done for free?

So to be fair I think we should acknowledge either a suitably
representative cross-section of the whole infrastructure, or none of
it.  It isn't fair to acknowledge just the squeaky wheels.
-v


Date:        Fri, 24 Aug 90 20:23:06 EDT
From:        Michael Barr <INHB@MUSICB.MCGILL.CA>

                               First announcement
                     INTERNATIONAL CATEGORY THEORY MEETING
                          Montreal, June 23--30, 1991

        We are  planning an  international meeting  in general  category
        theory during the last week in June.  There will be a scientific
        program committee chaired by Michael Makkai.

        There will be registration fee of $150 (students $50).  We  will
        be arranging the possibility of renting dormitory rooms at about
        $32 per night (there  may be a special  rate for students).   Of
        course, hotel rooms are also available.

        A  later   announcement  will   give  more   details  concerning
        abstracts, accomodations, etc.  Please contact one of us if  you
        wish to receive that second announcement.


        Michael Barr                        Thomas Fox
        Math. Dept., McGill University      4656 Jeanne Mance
        805 Sherbrooke St. W                Montreal, Quebec
        Montreal, Quebec                    Canada H2V 4J4
        Canada H3A 2K6

        Tel. (Office:) (514) 398-3806
        Tel. (Home:) (514) 342-2658         (514) 844-5433
        Email: inhb@mcgillb.bitnet          mt16@mcgilla.bitnet
        Email: inhb@musicb.mcgill.ca        mt16@musica.mcgill.ca


Date:        Mon, 27 Aug 90 08:41:04 EDT
From:        Michael Barr       <INHB@MUSICB.MCGILL.CA>

To all those who have responded to our first announcement:
(As well as those who haven't).  Please write to me only if you DO NOT
normally receive these bulletins.  I will put the second announcement out
on this net in any case.  I should have made it clear that you
should write only if you wanted a physical announcement, in which case
please send a physical address.
Michael Barr
