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.
    • CommentAuthorPeter Heinig
    • CommentTimeJun 11th 2017
    • (edited Jun 11th 2017)

    Added a pointer to adjoint functors and triangle identities to the entry whiskering. Feel that an encyclopedia entry on that operation should mention these two other entries.

    • CommentRowNumber2.
    • CommentAuthorTodd_Trimble
    • CommentTimeJun 11th 2017

    I don’t know if I agree with that sentence (“the most important”), although I won’t say it’s obviously wrong.

    One thing should be clarified, however: the nLab isn’t quite an encyclopedia, and it would be somewhat misleading to think of it this way. Some of it may look that way, and some of us may have encyclopedist tendencies on occasion, but the true situation is a little more complicated. If you haven’t already, you might have a look at About.

    • CommentRowNumber3.
    • CommentAuthorUrs
    • CommentTimeJun 11th 2017

    Let’s just write “An important use of whiskering” instead. That carries all the intended information.

    • CommentRowNumber4.
    • CommentAuthorPeter Heinig
    • CommentTimeJun 11th 2017

    Thanks. Neither the use of the word “encyclopedia” nor the phrase “the most important” were chosen with care by me, sorry. But thanks for taking them seriously, words are to be taken seriously.

    • CommentRowNumber5.
    • CommentAuthorPeter Heinig
    • CommentTimeJul 26th 2017

    Added a reference and some “Related concepts”-information to whiskering. Whiskering are typical and “natural” examples of pasting diagrams which along A. J. Power’s method of proof give boundary walks which are non-trails.

    • CommentRowNumber6.
    • CommentAuthorUrs
    • CommentTimeJul 27th 2017
    • (edited Jul 27th 2017)

    Peter, you added under “Related entries” the words

    • Usual whiskering diagrams have 1-cells which constitute a plane digraph. The boundary walk of the exterior face has arc-repetitions. (Two repetitions of multiplicity two, for that matter. These terms are explained in plane digraphs.

    We may have mentioned a few times before that we like to stick to the convention that the sections titled “Related entries” contain mostly just a plain link list, while any actual information should go into the main body of the text. The idea is that “Related entries” gives the reader a quick overview of just that: related entries.

    So in principle your text should go under “Properties”. But it seems such a trivial and unimportant property that I wouldn’t quite think it needs to be said.

    • CommentRowNumber7.
    • CommentAuthorPeter Heinig
    • CommentTimeJul 27th 2017

    Urs, thanks for this comment.

    while any actual information should go into the main body of the text.

    Your mentionings of this editorial principle I had read, but somehow not internalized yet. Had simply thought it to be an improvement.

    So in principle your text should go under “Properties”. But it seems such a trivial and unimportant property that I wouldn’t quite think it needs to be said.

    The passage has been removed. Will remember that the “Related Concept” section is not to contain anything else than lists of related terms.

    I agree that that the passage should not go into whiskering. I am less sure whether to agree that this is a

    trivial and unimportant property

    but it should go into the systematic and detailed treatment of A. J. Power’s pasting theorem, where it belongs, and which hopefully will be ready soon.

    Thanks again.

    • CommentRowNumber8.
    • CommentAuthorUrs
    • CommentTimeJul 28th 2017

    Peter, what is your current email address?

  1. added definition of whiskering in dependent type theory


    diff, v12, current

    • CommentRowNumber10.
    • CommentAuthorUrs
    • CommentTimeAug 18th 2023

    added pointer to:

    diff, v16, current