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    • CommentRowNumber1.
    • CommentAuthorYaron
    • CommentTimeDec 14th 2010

    Started adjoint lifting theorem. For now, it only includes a version for lifting left adjoints (I still haven’t read Johnstone’s 1975 paper for the case of right adjoints). I hope there is no substantial error in the appliaction for cocompleteness.

    • CommentRowNumber2.
    • CommentAuthorzskoda
    • CommentTimeDec 20th 2010
    • (edited Dec 20th 2010)

    Welcome the entry and welcome the contributor!

    By the way, the only place where I know that people cite Categories for Working Mathematicians by “Categories Work” is nlab. When I saw it first time I was very confused. I find usage of non-insightful slang unfriendly to the outsiders (I count as an outsider in category theory). It makes categories not work for outsiders.

    • CommentRowNumber3.
    • CommentAuthorYaron
    • CommentTimeDec 20th 2010

    Thank you, Zoran!

    Regarding “Categories Work,” I think that Mac Lane himself used it (in his Mathematics, Form and Function).

    • CommentRowNumber4.
    • CommentAuthorMike Shulman
    • CommentTimeDec 21st 2010

    I hadn’t heard it before coming to the ’lab either, although I knew immediately what it meant when I heard it.

    • CommentRowNumber5.
    • CommentAuthorYaron
    • CommentTimeJan 29th 2011

    Added a sketch of proof in adjoint lifting theorem.

    • CommentRowNumber6.
    • CommentAuthorTodd_Trimble
    • CommentTimeAug 7th 2014

    Looking over adjoint lifting theorem (a very useful result), it seems to me the proof could probably be made to look simpler by using string diagrams. I would undertake this myself, except that I am really no good at graphics. Perhaps I should hand-draw and upload, or do people have a better suggestion?

    • CommentRowNumber7.
    • CommentAuthorzskoda
    • CommentTimeAug 7th 2014
    • (edited Aug 7th 2014)

    If you have another proof than it should be added to the existing, not replacing it. For example, I always had difficulty in understanding any categorical mathematics involving string diagrams so I am not a good audience for a string diagram involving proofs even if they are internally simpler.

    • CommentRowNumber8.
    • CommentAuthorTodd_Trimble
    • CommentTimeAug 7th 2014

    I understand; you’re not alone. Yes, I was hoping just to add, not erase and replace.

    • CommentRowNumber9.
    • CommentAuthorMike Shulman
    • CommentTimeAug 7th 2014

    By the same token, hand-drawn pictures would be better than no pictures!

    • CommentRowNumber10.
    • CommentAuthorDavidRoberts
    • CommentTimeAug 8th 2014

    I second Mike’s comment