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    • CommentRowNumber1.
    • CommentAuthorTodd_Trimble
    • CommentTimeSep 17th 2018

    I am periodically asked what has become of Joyal’s Cat Lab, which seems to be dormant or moribund. Has anyone asked him about this recently?

    There would need to be a certain amount of clean-up, but we might need his permission…

    • CommentRowNumber2.
    • CommentAuthorMike Shulman
    • CommentTimeSep 17th 2018

    Oh, phooey, if I’d thought of it a week ago I could have asked him about it at the VV memorial conference.

  1. Just remind me what the goal would be here? I think it is clear that the project is no longer active. Is it that people would like to begin editing it? Or that we should put up some message that the project is no longer active?

    • CommentRowNumber4.
    • CommentAuthoruser 170039
    • CommentTimeSep 18th 2018
    To be sure, I was the one who was periodically asking Todd Trimble about it. Now let me try to answer Richard Williamson's questions (of course, it's entirely my personal opinion): (1) What was the initial goal for starting Joyal's Catlab? Is the continuation of the same goal a problem? (2) As it currently stands, I think that the commutative diagrams really need editing, (3) Maybe that would be a good idea if people are not willing to continue it.
  2. Thanks very much for joining the discussion! By “goal”, I meant just what we would be asking Joyal about.

    Personally I don’t think I’ve seen anything at the CatLab that distinguishes the content from what would be suitable for the main nLab. But no problem if others feel differently.

    • CommentRowNumber6.
    • CommentAuthorTodd_Trimble
    • CommentTimeSep 18th 2018

    I might be slightly mistaken, but I think Joyal had wanted to put his imprimatur on his CatLab, and thus wanted personal oversight over any substantial edits (such as exposition). I’d bet money he wouldn’t mind at all if someone fixed things like commutative diagrams, but I think we should still ask whether he would mind.

    It’s been a long time since my last contact with him, so I’d prefer it not be me to reach him about this, although I will if no one else volunteers.

    • CommentRowNumber7.
    • CommentAuthorTodd_Trimble
    • CommentTimeOct 7th 2018

    Okay, I wrote André about this.

    • CommentRowNumber8.
    • CommentAuthorTodd_Trimble
    • CommentTimeOct 7th 2018

    And now (as Richard will know when he reads this), André has graciously written back, giving permission to perform fixes.

    • CommentRowNumber9.
    • CommentAuthorRichard Williamson
    • CommentTimeOct 8th 2018
    • (edited Oct 9th 2018)

    Password sent to Todd now.

    I’ve also switched on nForum announcements for the CatLab, in case Todd or anybody else wishes to make use of these.

    • CommentRowNumber10.
    • CommentAuthorzskoda
    • CommentTimeOct 10th 2018
    • (edited Oct 10th 2018)
    > Personally I don’t think I’ve seen anything at the CatLab that distinguishes the content from what would be suitable for the main nLab. But no problem if others feel differently.

    By no means! Joyal started writing a complex of pages in structured way developing theory in an original and somewhat minimal way to achieve his goals. This can not be mixed with mixtures of stuff thrown on various pages on the lab. It is like the difference between the mixed notes and self consistent book. Thus the biggest inherent value is as a stand alone.

    Of course, the biggest problem is that xy diagrams are broken there since codecogs stopped serving them.
    • CommentRowNumber11.
    • CommentAuthorRichard Williamson
    • CommentTimeOct 10th 2018
    • (edited Oct 10th 2018)

    To me, I must say (this is not meant as a criticism) that it has never struck me as especially original. I think some of the material on distributors is probably the only thing I have seen that might not be considered standard. But as you say, it does have a certain organisational structure and perspective that comes from being a single person’s cohesive work. I am completely happy for it to exist :-)

    • CommentRowNumber12.
    • CommentAuthorFosco
    • CommentTime7 days ago
    • (edited 7 days ago)
    Is this a good place to advertise the esistence of koDi https://paolobrasolin.github.io/kodi/ ?
    • CommentRowNumber13.
    • CommentAuthorzskoda
    • CommentTime6 days ago
    Richard, the point is that the basic stuff is seen in shorter and more clear way. Say, Lurie's books are magnificent work but is the essence of the subject really that complicated. The part which I have seen from Joyal's expositions, especially his draft book of lectures written for Barcelona school 2008 have so many impressive shortcuts. But you should also know that so much of this which you find standard has been historically first suggested by Joyal (often not in published or generally circulated form). I do not see that somebody else in nLab community can provide similar level of clarity to the subject and to the fundamentals.
    • CommentRowNumber14.
    • CommentAuthorzskoda
    • CommentTime6 days ago
    Fosco, are you a spammer ? This discussion is about a very particular topic which your link is presumably not about.
    • CommentRowNumber15.
    • CommentAuthorTodd_Trimble
    • CommentTime6 days ago

    Zoran, I didn’t check out that link, but hopefully this Fosco is the same as Fosco Loregian who is a category theorist and friend of the nLab. (Fosco, could you explain a little more about your link?)

    • CommentRowNumber16.
    • CommentAuthorTodd_Trimble
    • CommentTime6 days ago

    Oh, I see: Fosco was linking to TeX-based software for commutative diagrams. This could be useful for nLabbers.

    • CommentRowNumber17.
    • CommentAuthorzskoda
    • CommentTime5 days ago

    But has nothing to do with Joyal, and i see just smple code out of context, no Readme file, even no name of which language the code is in. Just link thrown into discussion.

    • CommentRowNumber18.
    • CommentAuthorDavidRoberts
    • CommentTime5 days ago

    A link to a page that makes diagrams in a discussion which includes laments that diagrams no longer work on the CatLab. :-)

    • CommentRowNumber19.
    • CommentAuthorzskoda
    • CommentTime5 days ago

    I know David, but the link isunusableand this is not only about Catlab. Codecogs is broken in mainkab in my lab and so on. Link to 10 lines if diagram code in unknown language looks like google generated association, rather than a conversational replica. What is the language?

  3. The source code can be found here. It looks like a library for creating commutative diagrams in TikZ, i.e. it is a kind of layer on top of plain TikZ. It is written in LaTeX as far as I see, i.e. it just introduces some convenient syntax.

    I am planning to add TikZ support to the nLab as soon as time allows. I have also mentioned before the possibility of having some implementation-agnostic syntax for commutative diagrams; kodi is something along these lines, it seems, although more closely tied to TikZ than I was envisioning.

    • CommentRowNumber21.
    • CommentAuthorzskoda
    • CommentTime4 days ago

    Implementing the TikZ is a difficult project. If we have it then anyway many paths will be open for further development. The diagram support is of course our main need.

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