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  1. This is my first (substantial) contribution to the nLab, so forgive my likely ineptitude. This wants to be a initial stub, everything is basically scraped from the reference and this post: Clearly a lot of material can be added, included a better definition and clearer examples. It’s also quite necessary to make a page for decorated cospans. I might start it myself later this month.


    v1, current

    • CommentRowNumber2.
    • CommentAuthorDavidRoberts
    • CommentTimeJul 20th 2019

    Just want to say it looks good. Sure, there might be some minor formatting (maybe a sidebar or something, table of contents) to do, but it’s certainly far better than some other newbies.

    • CommentRowNumber3.
    • CommentAuthorUrs
    • CommentTimeJul 20th 2019

    Hi mattecapu,

    could you maybe add an explicit definition of “structured cospan”? As in “A structured cospan is…”.

    Currently the only place where we learn what is meant is only implicit in the third bullet item of the definition of that double category.

    Otherwise there is some grammar to be fixed, various singular/plural issues.

    • CommentRowNumber4.
    • CommentAuthorDavid_Corfield
    • CommentTimeJul 20th 2019

    Yes, a good start. Are there any standard ways to motivate these constructions?

    • CommentRowNumber5.
    • CommentAuthorMike Shulman
    • CommentTimeJul 20th 2019

    Renamed page to match nLab convention of singular page titles.

    diff, v2, current

    • CommentRowNumber6.
    • CommentAuthorMike Shulman
    • CommentTimeJul 20th 2019

    I agree that the page is a good start. One suggestion I might make is to start with motivation for the concept in general, rather than only in contrast to decorated cospans; the comparison to decorated cospans could then be a section lower down on the page.

  2. Added an explicit definition of structured cospan.


    diff, v4, current

    • CommentRowNumber8.
    • CommentAuthormattecapu
    • CommentTimeJul 21st 2019
    Hello everyone,
    I did my best to kick-start the page although I'm actually no expert on this topic, I'm learning-by-contributing this stuff. Hence if someone else has better motivation/definitions for the concept, I'd be happy to read them as well!
    The one I included stems directly from Kenny Courser's talk, where they are basically introduced like this. There might be more in his thesis, so I will look into it.
    • CommentRowNumber9.
    • CommentAuthorUrs
    • CommentTimeJul 21st 2019

    replaced quiver with directed graph.

    Notice that “quiver” is a concept with an attitude and it’s not the relevant attitude here.

    diff, v5, current

    • CommentRowNumber10.
    • CommentAuthorJoe Moeller
    • CommentTimeNov 16th 2019

    Added a link to the paper Structured Cospans by Baez and Courser.

    diff, v6, current

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