August 1990 - Categories - categories.org.au

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by Michael Barr 27 Aug '90

27 Aug '90

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

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by Michael Barr 25 Aug '90

25 Aug '90

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(a)mcgillb.bitnet mt16(a)mcgilla.bitnet Email: inhb(a)musicb.mcgill.ca mt16(a)musica.mcgill.ca

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Re: commutative diagrams formatting package
by pratt＠cs.stanford.edu 16 Aug '90

16 Aug '90

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by unknown＠categories.mta.ca 15 Aug '90

15 Aug '90

*** 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

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commutative diagrams
by Paul Taylor 14 Aug '90

14 Aug '90

*** 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?

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Dense frame maps
by PJOHNSON＠Wesleyan.bitnet 01 Aug '90

01 Aug '90

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?

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