Not signed in (Sign In)

Not signed in

Want to take part in these discussions? Sign in if you have an account, or apply for one below

  • Sign in using OpenID

Site Tag Cloud

2-category 2-category-theory abelian-categories adjoint algebra algebraic algebraic-geometry algebraic-topology analysis analytic-geometry arithmetic arithmetic-geometry book bundles calculus categorical categories category category-theory chern-weil-theory cohesion cohesive-homotopy-type-theory cohomology colimits combinatorics complex complex-geometry computable-mathematics computer-science constructive cosmology deformation-theory descent diagrams differential differential-cohomology differential-equations differential-geometry digraphs duality elliptic-cohomology enriched fibration foundation foundations functional-analysis functor gauge-theory gebra geometric-quantization geometry graph graphs gravity grothendieck group group-theory harmonic-analysis higher higher-algebra higher-category-theory higher-differential-geometry higher-geometry higher-lie-theory higher-topos-theory homological homological-algebra homotopy homotopy-theory homotopy-type-theory index-theory integration integration-theory k-theory lie-theory limits linear linear-algebra locale localization logic mathematics measure-theory modal modal-logic model model-category-theory monad monads monoidal monoidal-category-theory morphism motives motivic-cohomology nforum nlab noncommutative noncommutative-geometry number-theory of operads operator operator-algebra order-theory pages pasting philosophy physics pro-object probability probability-theory quantization quantum quantum-field quantum-field-theory quantum-mechanics quantum-physics quantum-theory question representation representation-theory riemannian-geometry scheme schemes set set-theory sheaf sheaves simplicial space spin-geometry stable-homotopy-theory stack string string-theory superalgebra supergeometry svg symplectic-geometry synthetic-differential-geometry terminology theory topology topos topos-theory tqft type type-theory universal variational-calculus

Vanilla 1.1.10 is a product of Lussumo. More Information: Documentation, Community Support.

Welcome to nForum
If you want to take part in these discussions either sign in now (if you have an account), apply for one now (if you don't).
    • CommentRowNumber1.
    • CommentAuthorTodd_Trimble
    • CommentTimeAug 6th 2012
    • CommentRowNumber2.
    • CommentAuthorTobyBartels
    • CommentTimeAug 6th 2012

    Can we just make this in a closed category? The monoidal operation doesn’t appear to be used here.

    • CommentRowNumber3.
    • CommentAuthorTodd_Trimble
    • CommentTimeAug 6th 2012

    Sure. But closed monoidal categories are far more common in practice, and since any closed category embeds in a closed monoidal category by a fully faithful closed functor, the extra generality doesn’t seem significant to me.

    • CommentRowNumber4.
    • CommentAuthorTobyBartels
    • CommentTimeAug 6th 2012

    A lot of categories are more obviously closed than monoidal. It seems strange to ask the reader to consider whether BanBan has a tensor product compatible with its closed structure when discussing the dual, when this has nothing directly to do with it.

    • CommentRowNumber5.
    • CommentAuthorTodd_Trimble
    • CommentTimeAug 6th 2012

    As I say, Toby, go ahead and change it if you like.

    • CommentRowNumber6.
    • CommentAuthorTobyBartels
    • CommentTimeAug 6th 2012

    I’ve changed it enough to be happy. (^_^)

    • CommentRowNumber7.
    • CommentAuthorMike Shulman
    • CommentTimeAug 6th 2012

    It seems to me that it would be less circular to say that in a star-autonomous category the dual of AA is AA\multimap \bot where \bot is the “dualizing object” (rather than “the dual of the monoidal unit”).

    Also, I find it very confusing that “the dual” of AA, in the sense of this new page, is not necessarily “a dual” of AA, in the sense of the page dual object. Is there anything we can do about that?

    • CommentRowNumber8.
    • CommentAuthorTodd_Trimble
    • CommentTimeAug 6th 2012

    is the “dualizing object”

    Yeah, I just blanked out on this bit of standard terminology when I wrote the circular phrase. Fixed.

    Also, I find it very confusing that “the dual” of A, in the sense of this new page, is not necessarily “a dual” of A, in the sense of the page dual object.

    Several pages need some fixing up. I’ll see what I can do, and report back.

    • CommentRowNumber9.
    • CommentAuthorTodd_Trimble
    • CommentTimeAug 6th 2012
    • (edited Aug 6th 2012)

    Okay, made some clarifying/disambiguating remarks at dual object in a closed category (note the change of title), dualizable object, category with duals (adding, after *\ast-autonomous category, closed categories which again “do not really belong in the list”), and most significantly at predual. At the last, I edited to say that the term is most commonly encountered in the sense of “dual object in a closed category”, and that for other monoidal senses of dual it boils down to some other differently named concept.

    In other words, I followed what Zoran called (rather sweetly, I thought) “Urs’s principle”, making changes and reporting back. Please feel free to improve, or say something here if you disagree with the edits.

    Edit: could be a cache bug problem; dual object in a closed monoidal category isn’t redirecting to dual object in a closed category, as I hoped it would.

    • CommentRowNumber10.
    • CommentAuthorMike Shulman
    • CommentTimeAug 6th 2012

    That helps; thanks!

    • CommentRowNumber11.
    • CommentAuthorTobyBartels
    • CommentTimeAug 6th 2012

    could be a cache bug problem

    It is; you can tell if you try to edit, which will bounces you to the home page if it’s the cache bug.

    • CommentRowNumber12.
    • CommentAuthorUrs
    • CommentTimeAug 13th 2012

    I have cleared the cache of dual object in a closed category.

    • CommentRowNumber13.
    • CommentAuthorTobyBartels
    • CommentTimeAug 13th 2012

    It’s the other one that needed to be cleared (but it has been, or cleared itself). (Also, do we really want a table of contents with only one entry? An entry whose header doesn’t fully match its content either.)

    • CommentRowNumber14.
    • CommentAuthorTodd_Trimble
    • CommentTimeAug 14th 2012

    (Also, do we really want a table of contents with only one entry? An entry whose header doesn’t fully match its content either.)

    In dual object in a closed category, I changed the section title from “Definition” to “Conventional Meaning” (that’s the closest description that occurred to me, but feel free to change).

    I guess Urs, by creating a table of contents, is simply preparing for a future where there is more than one section. It looks a little funny now, maybe, but I think it does no harm. :-)

    • CommentRowNumber15.
    • CommentAuthorUrs
    • CommentTimeAug 14th 2012
    • (edited Aug 14th 2012)

    It’s the other one that needed to be cleared

    You mean the one of dual object in a closed monoidal category? I would have thought so, too, but it turns out that’s not how the system works: the cache file of that entry didn’t exist when I went to remove cache files. I guess the cache file is correctly being renamed when the entry is being renamed, but then something else goes wrong.

    I guess Urs, by creating a table of contents, is simply preparing for a future where there is more than one section.

    Yes. And now there are two sections. In fact, I would be inclined to restructure the text at “Conventional meaning” into “Definition” and “Properties - Relation to other notions” and “Examples and counterexamples”. But I won’t do that right now.

    • CommentRowNumber16.
    • CommentAuthorTobyBartels
    • CommentTimeAug 14th 2012

    I guess the cache file is correctly being renamed when the entry is being renamed, but then something else goes wrong.

    That’s funny, that’s not how it used to go wrong. But they also used to clear themselves after a while, which is what I thought must have happened here.