Not signed in (Sign In)

Start a new discussion

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 bundles calculus categorical categories category category-theory chern-weil-theory cohesion cohesive-homotopy-type-theory cohomology colimits combinatorics 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 finite 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 internal-categories k-theory lie lie-theory limit limits linear linear-algebra locale localization logic manifolds mathematics measure-theory modal modal-logic model model-category-theory monads monoidal monoidal-category-theory morphism motives motivic-cohomology nforum nlab noncommutative noncommutative-geometry number 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 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.
    • CommentAuthorDavid_Corfield
    • CommentTimeSep 27th 2012

    I pasted in something Mike wrote on sketches and accessible models to sketch. But now it needs tidying up, and I’m wondering if it might have been better placed at accessible category. Alternatively we start a new page on sketch-theoretic model theory. Ideas?

    • CommentRowNumber2.
    • CommentAuthorMike Shulman
    • CommentTimeSep 27th 2012

    Putting it at accessible category sounds good to me.

    • CommentRowNumber3.
    • CommentAuthorDexter Chua
    • CommentTimeAug 29th 2016

    Added a small idea section and an example.

    • CommentRowNumber4.
    • CommentAuthorMike Shulman
    • CommentTimeNov 9th 2017

    Andrée Ehresmann pointed out on the catlist that our definition of sketch was actually the definition of a realized sketch, so I fixed our page to the more general version.

  1. The category of sketches has a well behaved symmetric monoidal structure that can be useful when discussing models of theories inside of models of theories, such as double categories or vector bundle groupoids. I thought it might be useful to have on the nlab page for sketches.

    Ben MacAdam

    diff, v18, current

  2. Was intending just to do a little tidying and book-keeping, but ended up rewriting the idea section as well, and giving, for my sins, the full details of a couple of examples; writing down the full details of a sketch in practise is a little more subtle than one might think if one has not tried it.

    diff, v21, current

    • CommentRowNumber7.
    • CommentAuthorTim_Porter
    • CommentTimeAug 9th 2020

    Fixed an insecure link, replacing it by a Numdam link.

    diff, v23, current

    • CommentRowNumber8.
    • CommentAuthorUrs
    • CommentTimeMar 21st 2021

    added pointer to:

    diff, v24, current

  3. In the previous version it was claimed that the tensor product of sketches was part of a symmetric monoidal structure on the category of sketches. That is wrong. I sketched the right statement (factors in the tensor product can be swapped if the specified limits and colimits commute), gave a reference, and gave an example (I think) where one can not switch the factors.

    Peter Arndt

    diff, v28, current

    • CommentRowNumber10.
    • CommentAuthorUrs
    • CommentTimeAug 24th 2021

    added pointer to the recent:

    diff, v29, current

    • CommentRowNumber11.
    • CommentAuthorUrs
    • CommentTimeAug 24th 2021

    added pointer to:

    diff, v30, current

Add your comments
  • Please log in or leave your comment as a "guest post". If commenting as a "guest", please include your name in the message as a courtesy. Note: only certain categories allow guest posts.
  • To produce a hyperlink to an nLab entry, simply put double square brackets around its name, e.g. [[category]]. To use (La)TeX mathematics in your post, make sure Markdown+Itex is selected below and put your mathematics between dollar signs as usual. Only a subset of the usual TeX math commands are accepted: see here for a list.

  • (Help)