Not signed in (Sign In)

A discussion forum about contributions to the nLab wiki and related areas of mathematics, physics, and philosophy.

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

2-category 2-category-theory abelian-categories adjoint algebra algebraic algebraic-geometry algebraic-topology analysis analytic-geometry arithmetic arithmetic-geometry beauty bundles calculus categories category category-theory chern-weil-theory cohesion cohesive-homotopy-theory cohesive-homotopy-type-theory cohomology 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 foundations functional-analysis functor galois-theory gauge-theory gebra geometric-quantization geometry goodwillie-calculus graph graphs gravity grothendieck group-theory harmonic-analysis higher higher-algebra higher-category-theory higher-differential-geometry higher-geometry higher-lie-theory higher-topos-theory history homological homological-algebra homotopy homotopy-theory homotopy-type-theory index-theory infinity integration-theory internal-categories k-theory kan lie lie-theory limit limits linear linear-algebra locale localization logic manifolds mathematics measure-theory modal modal-logic model model-category-theory monad monoidal monoidal-category-theory morphism motives motivic-cohomology nonassociative noncommutative noncommutative-geometry number-theory of operads operator operator-algebra order-theory pasting philosophy physics planar 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-theory subobject 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.

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).

- Discussion Type
- discussion topicobservable
- Category Latest Changes
- Started by zskoda
- Comments 8
- Last comment by Tim_van_Beek
- Last Active Apr 9th 2010

New entry observable wanted at many entries. For now the very basic stuff, with a view toward maximal generality.

- Discussion Type
- discussion topicsoliton
- Category Latest Changes
- Started by zskoda
- Comments 3
- Last comment by zskoda
- Last Active Apr 9th 2010

- Discussion Type
- discussion topicThesis finished!
- Category Latest Changes
- Started by Guest
- Comments 16
- Last comment by Tim_Porter
- Last Active Apr 9th 2010

- I have put a copy of my thesis, as it is being handed up for examination, on my personal web.

David Roberts

- Discussion Type
- discussion topiccombinatorics
- Category Latest Changes
- Started by zskoda
- Comments 5
- Last comment by zskoda
- Last Active Apr 9th 2010

Maybe some could be interested in reviewing it (Toby?).

- Discussion Type
- discussion topicunbiased composites in double categories
- Category Latest Changes
- Started by Mike Shulman
- Comments 6
- Last comment by Eric
- Last Active Apr 8th 2010

Added some comments about the possibility of 2-dimensional unbiased composites in double categories.

- Discussion Type
- discussion topiccoinductive Trimble oo-categories
- Category Latest Changes
- Started by Mike Shulman
- Comments 26
- Last comment by DavidRoberts
- Last Active Apr 8th 2010

I added some comments to Trimble n-category regarding a coinductive way to state the definition, which I think is very clean and neat, and also a little mind-blowing.

- Discussion Type
- discussion topicsmooth Lorentzian space
- Category Latest Changes
- Started by Urs
- Comments 10
- Last comment by Urs
- Last Active Apr 7th 2010

expanded the previously pretty empty entry smooth Lorentzian space.

I added some standard definitions for smooth Lorentzian manifolds and then a discussion on how a time orientation without closed future-directed curves induces the structure of a category that is a poset, where a morphism witnesses the fact that is a point in the future of .

- Discussion Type
- discussion topicIan: latest changes
- Category Latest Changes
- Started by Ian_Durham
- Comments 10
- Last comment by Andrew Stacey
- Last Active Apr 7th 2010

- As per someone's suggestion, I am going to do what Zoran does and have one, continuously running forum topic with my latest changes.

My latest change: added response to Zoran's query at quantum mechanics.

- Discussion Type
- discussion topiccontributors to algebraic geometry
- Category Latest Changes
- Started by zskoda
- Comments 4
- Last comment by zskoda
- Last Active Apr 7th 2010

While Prof. Joyal in his joyalscatlab keeps the lists of contributors to category theory and to homological algebra, I thought it might be useful to have some complementary list for 2-3 other fields in our nlab. But this could be too much work. So I restrained with contributors to algebraic geometry, as over 20 are alerady present in the nlab anyway (algebraic geometry has much being intertwined with the development of category theory since Serre and Grothendieck). Created Jean-Pierre Serre and Shigeru Mukai, wanted also at the Timeline entry; and David Mumford. This entry should be useful as we do not have top entry of contents for alegbraic geometry. (and I do not plan it soon).

- Discussion Type
- discussion topicDonaldson-Thomas invariant
- Category Latest Changes
- Started by zskoda
- Comments 2
- Last comment by zskoda
- Last Active Apr 7th 2010

Idea at Donaldson-Thomas invariant, hopefully correct to zeroth approximation, but not sure. Related update of Dominic Joyce.

- Discussion Type
- discussion topicmodel structure for Cartesian fibrations
- Category Latest Changes
- Started by Urs
- Comments 4
- Last comment by Urs
- Last Active Apr 7th 2010

renamed model structure on marked simplicial oversets to model structure for Cartesian fibrations

merged the material that was at marked simplicial set (now marked simplicial set > history) into this entry

expanded the entry a bit, but still working on it...

- Discussion Type
- discussion topicquasi-category theory contents
- Category Latest Changes
- Started by Urs
- Comments 1
- Last comment by Urs
- Last Active Apr 7th 2010

created floating toc quasi-category theory contents

there is still a lot left to type in concerning quasi-category theory, but it seemed to me about time to collect what is there and organize it, so that one can see what we have, what is missing, and so that readers find their way to their information

- Discussion Type
- discussion topicspam at factorization algebra
- Category Latest Changes
- Started by Urs
- Comments 3
- Last comment by Eric
- Last Active Apr 7th 2010

some Anonymous Coward added an unmotivated link to some web-hosting site at factorization algebra. I have rolled back the entry to before that edit.

I am wondering if the creatures who do such things wiill at least eventually learn something from reading about things like factorization algebras...

- Discussion Type
- discussion topiclarge N limit
- Category Latest Changes
- Started by zskoda
- Comments 1
- Last comment by zskoda
- Last Active Apr 7th 2010

We should have an entry on large N limit gradually. But sometimes it can be treated as a semiclassical limit. I quoted a reference by Yaffe where I originally read of that approach to the entry semiclassical expansion.

- Discussion Type
- discussion topicgeneralized multicategories
- Category Latest Changes
- Started by Mike Shulman
- Comments 1
- Last comment by Mike Shulman
- Last Active Apr 6th 2010

I have been greatly expanding the entry generalized multicategory, to work up gradually from the most explicit and easy-to-understand Leinster definition through profunctors, double categories, and up to the most general situation considered in my paper with Geoff, with examples. There's lots more left to do, but I have to run to a seminar now.

- Discussion Type
- discussion topicGrothendieck's existence theorem
- Category Latest Changes
- Started by zskoda
- Comments 1
- Last comment by zskoda
- Last Active Apr 6th 2010

New entry Grothendieck existence along with many redirects. New person entry Steven Kleiman. Pdf link to write up of Gerd Faltings' 1995 Bonn lectures at moduli space of bundles and some new reference here and there.

- Discussion Type
- discussion topicDold fibrations
- Category Latest Changes
- Started by DavidRoberts
- Comments 1
- Last comment by DavidRoberts
- Last Active Apr 6th 2010

I fixed up an obvious error in a claim at Dold fibration: the counterexample there showed the converse of what was claimed (and I think the error was due to me). Now I'd like to find a proper counterexample, so I'll ask on MathOverflow, in case anyone has one up their sleeve.

- Discussion Type
- discussion topichom-object in a quasi-category
- Category Latest Changes
- Started by Urs
- Comments 1
- Last comment by Urs
- Last Active Apr 5th 2010

created hom-object in a quasi-category

- Discussion Type
- discussion topicGrothendieck fibration
- Category Latest Changes
- Started by Mike Shulman
- Comments 5
- Last comment by Tim_Porter
- Last Active Apr 5th 2010

Did some reorganizing at Grothendieck fibration.

- Discussion Type
- discussion topicSVG Editor HowTo
- Category Latest Changes
- Started by Andrew Stacey
- Comments 12
- Last comment by Andrew Stacey
- Last Active Apr 4th 2010

Created SVG Editor HowTo whilst trying to convert the codecogs monstrosity at exercise in groupoidification - the path integral to SVG (conversion happening in the Sandbox for the moment, and definitely not finished yet).

- Discussion Type
- discussion topicfunctor
- Category Latest Changes
- Started by Eric
- Comments 213
- Last comment by Eric
- Last Active Apr 3rd 2010

Asked a question at functor.

- Discussion Type
- discussion topicA partial addition and some added details
- Category Latest Changes
- Started by Ian_Durham
- Comments 3
- Last comment by Ian_Durham
- Last Active Apr 3rd 2010

- I began working on a page for the GNS construction but started dozing off at my keyboard (so it needs someone to help finish it). Also I added a note on QBism and category theory to the page on quantum states. In it I assert that category theory is, in essence, a theory about relations (bear with me on this one - read the entry).

- Discussion Type
- discussion topicquantum state
- Category Latest Changes
- Started by Ian_Durham
- Comments 12
- Last comment by Ian_Durham
- Last Active Apr 3rd 2010

- Added page quantum state.

- Discussion Type
- discussion topic‘folk’
- Category Latest Changes
- Started by TobyBartels
- Comments 4
- Last comment by Mike Shulman
- Last Active Apr 2nd 2010

I added a brief note to folk model structure to reflect the other terms suggested on another thread.

- Discussion Type
- discussion topicmonoidal bicategories
- Category Latest Changes
- Started by Mike Shulman
- Comments 4
- Last comment by Mike Shulman
- Last Active Apr 2nd 2010

Started monoidal bicategory with a bunch of references to the tortuous literature on braided and symmetric things. Please correct me if I left anything out. It would be nice to have the "accepted/correct" definitions here eventually, for reference.

- Discussion Type
- discussion topicSome updates
- Category Latest Changes
- Started by Ian_Durham
- Comments 7
- Last comment by Ian_Durham
- Last Active Apr 2nd 2010

- Didn't have much free time, but managed to add a little bit to Stokes phenomenon and responded to Zoran's query about Birkhoff's theorem. I suggested we rename it "Birkhoff-von Neumann theorem" so as not to confuse it with other similarly titled theorems.

- Discussion Type
- discussion topicGroup Presentation
- Category Latest Changes
- Started by Tim_Porter
- Comments 2
- Last comment by zskoda
- Last Active Apr 1st 2010

I have started an entry on group presentations. This will lead to a discussion of identities among relations as well as feeding into the rewriting page.

- Discussion Type
- discussion topicNew page: [[proper subset]]
- Category Latest Changes
- Started by TobyBartels
- Comments 41
- Last comment by Mike Shulman
- Last Active Mar 31st 2010

Not much there, but I created it: proper subset.

- Discussion Type
- discussion topicdecalage
- Category Latest Changes
- Started by Urs
- Comments 8
- Last comment by Urs
- Last Active Mar 30th 2010

edited decalage a bit

there was the statement that is a "fibration". I made that Kan fibration. Is that right?

- Discussion Type
- discussion topicClassical field theory
- Category Latest Changes
- Started by Ian_Durham
- Comments 3
- Last comment by Ian_Durham
- Last Active Mar 29th 2010

- I added a query to classical field theory.