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 internal-categories k-theory lie-theory limits linear linear-algebra locale localization logic mathematics measure 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 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).

nLab > Latest Changes: signature

Bottom of Page

1 to 16 of 16

  1.  
    • CommentRowNumber1.
    • CommentAuthorUrs
    • CommentTimeMay 5th 2010

    at signature we should eventually think about some disambiguation. There are many things in math called “signature”- For instance the signature of a permutation.

    • CommentRowNumber2.
    • CommentAuthorTodd_Trimble
    • CommentTimeMay 5th 2010
    • (edited May 5th 2010)
    I just added a disambiguation to signature, and wrote signature (disambigation) (stub).
    • CommentRowNumber3.
    • CommentAuthorUrs
    • CommentTimeMay 5th 2010

    thanks, Todd. For the moment I just added a link at the disambiguation page also to your signature-page.

    • CommentRowNumber4.
    • CommentAuthorIan_Durham
    • CommentTimeMay 5th 2010

    Not to resurrect a sore subject, but we tend to also use the word signature in describing metrics. Not sure how that fits in with what is already there.

    • CommentRowNumber5.
    • CommentAuthorTodd_Trimble
    • CommentTimeMay 5th 2010
    True, Ian, and that's a special case of signature of a quadratic form (as mentioned at signature (disambiguation)), which is to be written.
    • CommentRowNumber6.
    • CommentAuthorUrs
    • CommentTimeMay 5th 2010

    another major signature-topic would be the signature-genus. Also to be written…

    • CommentRowNumber7.
    • CommentAuthorUrs
    • CommentTimeMay 5th 2010

    right, I see we are in trouble already: elliptic cohomology had a link to signature, but meant is the signature genus. Now it points to signature in logic.

    Todd, if you don’t mind, I am now going to name the disambiguation page just “signature”, so that in case of doubt people see the disambiguation page, and then I will rename your signature enttry into something more specific. What would be a good choice. Maybe “signature (in logic)” ?

    • CommentRowNumber8.
    • CommentAuthorTodd_Trimble
    • CommentTimeMay 6th 2010
    Of course I don't mind -- thanks, Urs.

    I've been writing a section on the language of the signature which ought to eventually include the classical syntactic account (with variables, terms, atomic formulas, and all that), but really I'm writing a slightly experimental description of the categorical way of viewing the language. The idea is basically to tie in with first-order Boolean-valued hyperdoctrines and describe the language of a signature as an initial hyperdoctrine in an appropriate sense. I jotted down what I am driving at at signature.
    • CommentRowNumber9.
    • CommentAuthorDavidRoberts
    • CommentTimeMay 6th 2010

    Cache bug is messing up the signature, signature (in logic) and signature (disambiguation) pages. I can’t get to the last one, as it redirects to signature, which for me is what is now signature (in logic).

    • CommentRowNumber10.
    • CommentAuthorUrs
    • CommentTimeMay 6th 2010
    • (edited May 6th 2010)

    Todd,

    there was probably a misunderstanding. While you write

    Of course I don’t mind

    you then reverted my changes when you

    jotted down what I am driving at at signature.

    I have now re-reverted it. Let’s see if we can agree on this:

    • the page signature (in logic) contains the material that a few hours back you typed into signature;

    • the page signature is what was originally your “signature (disambiguation)”. I think if there is need for a disambiguation page, then that disambiguation page must have just the ambiguous keyword as its title. Otherwise it won’t serve the desired purpose. Previous pages of this kind include for instance homotopy.

    • CommentRowNumber11.
    • CommentAuthorEric
    • CommentTimeMay 6th 2010

    FWIW, I like Urs suggested way to handle disambiguation, i.e. a page with simply the ambiguous name as title with a list of links to the various uses of that word. Maybe a few words thrown in to explain what’s going on as in signature.

    • CommentRowNumber12.
    • CommentAuthorTodd_Trimble
    • CommentTimeMay 6th 2010
    > you then reverted my changes

    I did? How did that happen? Sorry about that. I was trying to be reasonably careful and *not* do that sort of thing!
    • CommentRowNumber13.
    • CommentAuthorUrs
    • CommentTimeMay 6th 2010

    Probably the cache bug interfering. It keeps surprising me what that bug can do.

    But never mind, at least I could revert everything. sometimes it happens that the cache bug messes up things and then even prevents us from fixing them. Anyway, it’s all good now.

    • CommentRowNumber14.
    • CommentAuthorzskoda
    • CommentTimeMay 6th 2010

    My first association is Hirzebruch signature, regarding that the topology is the main topic in nlab so far…

    • CommentRowNumber15.
    • CommentAuthorTodd_Trimble
    • CommentTimeNov 25th 2012

    Slightly expanded signature of a permutation.

    • CommentRowNumber16.
    • CommentAuthorTodd_Trimble
    • CommentTimeSep 28th 2015

    Added the observation to signature of a permutation that computing the parity of the number of even-length cycles gives a perfectly respectable definition of the group homomorphism to {1,−1}\{1, -1\}.

1 to 16 of 16

  1.