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    • CommentRowNumber1.
    • CommentAuthorHarry Gindi
    • CommentTimeMay 9th 2010
    • (edited May 9th 2010)

    I dropped a query box over at Hurewicz fibration about a small difference of definition between the Lab and May's Concise Topology (in May, one only needs to have the RLP with respect to inclusions of CGWH spaces (into their cylinder objects at 0), while on the Lab, it says it must hold for all topological spaces.

    By the way, I like that page a lot, since it doesn't have an excessively long idea section (actually, there isn't any idea section, but I like that). It's written so it's easy to find the definition without wading through all of the clutter.

    I was wondering if it would be possible to swap the idea section and definition section around in a few articles and see if it makes them more readable. There's nothing more irritating than skipping the idea section only to find that the definition references the concepts introduced there. A definition should be readable entirely without having to read the idea section.

    • CommentRowNumber2.
    • CommentAuthorMike Shulman
    • CommentTimeMay 9th 2010

    I presume that “CGWH” means “compactly generated weak Hausdorff,” but it would have been better to say that. I believe the two definitions are actually different, although I don’t have an example to hand. Really, cofibrations and fibrations are defined by reference to any ambient topologically enriched category, which implies that the same map could be a co/fibration in one category but not in another larger or smaller one. I do have an example in the dual situation: all cofibrations in the category of compactly generated (weak Hausdorff) spaces are closed subspaces, but this is false for cofibrations in the category of all spaces, or even for merely compactly generated spaces (“k-spaces”).

    When I have time I’ll edit the entry some to this effect.

    • CommentRowNumber3.
    • CommentAuthorTodd_Trimble
    • CommentTimeMay 9th 2010

    I was wondering if it would be possible to swap the idea section and definition section around in a few articles and see if it makes them more readable.

    These things need to be looked at on a case-by-case basis. Why don’t you name the articles specifically, so we can have a look?

    A definition should be readable entirely without having to read the idea section.

    I am inclined to agree.

    • CommentRowNumber4.
    • CommentAuthorzskoda
    • CommentTimeMay 11th 2010

    I agree with Toby, each article has its own logic and difficulties and having rules to how to organize some article in general is counterproductive. Each article could have its own pedagogical organization according to the feeling of its creators.

    As you see I am back from the conference, but I returned back ssomehow sick (in unusual way, I still do not know if it is serious) and not in the shape to normally contribute yet.

    • CommentRowNumber5.
    • CommentAuthorMike Shulman
    • CommentTimeJan 8th 2019

    Mentioned the mixed model structure and the relation to Serre fibrations.

    diff, v27, current

  1. Moved the statements added in revision #20 of Serre fibration here (i.e. that a map is a Hurewicz fibration it it is one over a numerable cover of the codomain, and the corollary that numerable fiber bundles are Hurewicz fibrations.)


    diff, v28, current

    • CommentRowNumber7.
    • CommentAuthorzskoda
    • CommentTimeMar 25th 2021


    I do not understand, the moved paragraph is written about Serre fibration property, unlike the comment which says that it is about Hurewicz fibrations, if the paragraph is as it is now I do not see why it would be moved from Serre fibration.

    • CommentRowNumber8.
    • CommentAuthorUrs
    • CommentTimeMar 25th 2021

    Fixed the misprint (misprint, the or: Where wood is chopped, splinters must fall. Glad that Anonymous is joining me in chopping some wood here. Much appreciated.).

    • CommentRowNumber9.
    • CommentAuthorUrs
    • CommentTimeApr 16th 2021

    added the example of empty bundles (here)

    diff, v33, current

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