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 beauty bundles calculus categorical categories category category-theory chern-weil-theory cohesion cohesive-homotopy-theory 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 galois-theory 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 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 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 string string-theory superalgebra supergeometry svg symplectic-geometry synthetic-differential-geometry terminology theory topology topos topos-theory 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.
    • CommentAuthorUrs
    • CommentTimeJan 7th 2011
    • (edited Jan 7th 2011)

    Here is a nice simple test case that should serve to provide a good short example entry of the nJournal:

    Carlos Simpson had had occasion to cite the nnLab entry geometric realization of simplicial topological spaces as citaton [77] in his recent preprint.

    • Carlos Simpson, Local systems on proper algebraic VV-manifolds (pdf)

    It would be in everybody’s interest if instead of just the URL to the nnLab, he could cite this as a stable peer-reviewed entry in the nnJournal.

    Would anyone volunteer to formally referee the entry? It is very short and the material should be pretty standard. But it may be a good example and manifestly there is already need for it.

    (Since I am not a member of the editorial board to-be-formed, my call for referees here is not fully qualified, so I assume it would be useful in this case if we had non-anonymous referees, so that their name would serve as sufficient indication of expertise. )

    • CommentRowNumber2.
    • CommentAuthorTim_Porter
    • CommentTimeJan 7th 2011

    Urs: the link does not work.

    • CommentRowNumber3.
    • CommentAuthordomenico_fiorenza
    • CommentTimeJan 7th 2011
    • (edited Jan 7th 2011)

    can I edit geometric realization of simplicial topological spaces before we sumit it to a referee? (nothing crucial, just cosmetics)

    • CommentRowNumber4.
    • CommentAuthorTim_Porter
    • CommentTimeJan 7th 2011
    • (edited Jan 7th 2011)

    The correct link is here

    • CommentRowNumber5.
    • CommentAuthorUrs
    • CommentTimeJan 7th 2011

    Urs: the link does not work.

    Fixed it.

    can I edit geometric realization of simplicial topological spaces before we sumit it to a referee? (nothing crucial, just cosmetics)

    CERTAINLY! And even once it is submitted. And always. And not only are you allowed to, but you are encouraged to.

    All that changes with the submission for the nnLab entry is that there will be a remark being inserted that notifies whether some and which of its versions have been formally peer-reviewed.

  1. CERTAINLY! And even once it is submitted. And always. And not only are you allowed to, but you are encouraged to.

    I know, it’s just I’d like to clean that entry a bit before we freeze a version by peer-reviewing. The changes I have in mind are minimal: making two definitions of good in the sense of Segal and proper in the sense of May, a statement that goodnees implies properness citing David Roberts-Danny Stevenson unpublished work and possibly providing a link to it. Also we need a reference for the fact that if XX is proper then ||X|||X|||X||\to |X| is a homotopy equivalence, and be precise whether this is a weak homotopy equivalence or a homotopy equivalence. Finally we should add a reference to the Tammo tom Dieck work where the proof for the “XX good case” can be found.

  2. I’ve started editing the entry. Have to break now for a while, will complete editing later (in a short time).

  3. I’ve now done my edits. There’s a weird problem with the display of ||X||||X|| I’ve been unable to solve (the two ||’s appear extremely spaced to me).

    • CommentRowNumber9.
    • CommentAuthorAndrew Stacey
    • CommentTimeJan 7th 2011

    Use \Vert: $\Vert X \Vert$ produces X\Vert X \Vert

  4. Done. It’s better, but within the proposition enviroment (or the like) the result seems still not to be completely satisfactory.

    • CommentRowNumber11.
    • CommentAuthorUrs
    • CommentTimeJan 7th 2011

    I have added a bit more formatting (the missing Definition- and the missing Proof-Environment), made RobertStevenson a reference and added pointers to it (this way, once it is published, we don’t need to change the entry text, but just update the list of references) and added some cross-hyperlinks within the entry and some out of it. We need closed cofibration, by the way.

    • CommentRowNumber12.
    • CommentAuthorMike Shulman
    • CommentTimeJan 7th 2011

    ${\Vert X \Vert}$ with braces gets the spacing better, just as for single verts ${|X|}$.

    I changed the link to simplicial topological space to point to nice simplicial topological space, which seems more relevant. I observe that there is also substantial duplication between geometric realization of simplicial topological spaces and nice simplicial topological space. I would like to add a comment to the effect that proper simplicial topological spaces are just those that are Reedy cofibrant relative to the Strøm model structure, but I’m unsure which of those pages would be more appropriate for it.

    • CommentRowNumber13.
    • CommentAuthorTobyBartels
    • CommentTimeJan 8th 2011

    ${\Vert X \Vert}$ with braces gets the spacing better, just as for single verts ${|X|}$.

    Yes. This is basically an iTeX problem (possibly implicit in MathML, possibly something that could be fixed with complicated coding).

    • CommentRowNumber14.
    • CommentAuthorDavidRoberts
    • CommentTimeJan 9th 2011
    • (edited Jan 9th 2011)

    As at nice simplicial topological space, it would be worth pointing out that good \Rightarrow proper has its roots in a paper by Lewis, but is treated like a folk theorem. Danny and I have a generalisation of this result for a bicomplete topological concrete category. I’ve also linked ’closed cofibration’ to Hurewicz cofibration, where it is discussed and defined.

    • CommentRowNumber15.
    • CommentAuthorUrs
    • CommentTimeJan 9th 2011

    We still don’t have a referee, by the way.

  5. It seems that having the eyes of a potential referee pointed on geometric realization of simplicial topological spaces and related entries is improving them at a remarkable rate :)

    • CommentRowNumber17.
    • CommentAuthorUrs
    • CommentTimeJan 10th 2011
    • (edited Jan 11th 2011)

    I have added some further material:

    • stated the homeomorphism |Sing(X )| iso|dSing(X ) ||Sing(X_\bullet)| \simeq_{iso} | d Sing(X_\bullet)_\bullet |

    • split off the section with discussion of nice simplicial spaces as a separate subsection, so that we can later on easily sync it with nice simplicial topological space;

    • added the statement that proper = cofibrant in [Δ op,Top Strom] Reedy[\Delta^{op}, Top_{Strom}]_{Reedy};

    • added in a Proof-environment the remark that this implies that realizaiton of proper spaces is their homotopy colimit;

    • added the statement that |SingX |X |Sing X_\bullet| \to X_\bullet is cofibrant replacement in the Reedy structure (hence “properification”)

    • added the reference for “good implies proper”.

    • CommentRowNumber18.
    • CommentAuthorDavidRoberts
    • CommentTimeJan 11th 2011
    • (edited Jan 11th 2011)

    stated the homeomorphism |X |=|diag(SingX ) ||X_\bullet| = | diag (Sing X_\bullet)_\bullet |

    I don’t think this is true. If XX is a space considered as a constant simplicial space, then |X|=X|X| = X, diag(SingX)=SingXdiag(Sing X) = Sing X, and we know that XX is not homeomorphic to |SingX||Sing X|, only weakly homotopy equivalent.

    • CommentRowNumber19.
    • CommentAuthorUrs
    • CommentTimeJan 11th 2011
    • (edited Jan 11th 2011)

    Sorry, I meant the homeo |Sing(X )|=|diagSing(X ) ||Sing(X_\bullet)| = |diag Sing(X_\bullet)_\bullet|.