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nLab > Latest Changes: Grothendieck pretopology

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    • CommentRowNumber1.
    • CommentAuthorDmitri Pavlov
    • CommentTimeFeb 21st 2021

    Replaced the requirement of existence of all pullbacks with the requirement that pullbacks of covering families exist, to match SGA 4.

    Added a reference to SGA 4.

    diff, v21, current

    • CommentRowNumber2.
    • CommentAuthorDavidRoberts
    • CommentTimeFeb 23rd 2021

    I have no idea why the stronger definition was there for so long. It’s just not true in applications, most particularly the pretopology consisting of surjective submersions on the category of manifolds.

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