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- Discussion Type
- discussion topicAndrew Swan
- Category Latest Changes
- Started by Urs
- Comments 1
- Last comment by Urs
- Last Active Jan 14th 2021

brief

`category:people`

-entry for hyperlinking references at*Nielsen-Schreier theorem*

- Discussion Type
- discussion topicQuillen equivalence
- Category Latest Changes
- Started by Urs
- Comments 3
- Last comment by Hurkyl
- Last Active Jan 13th 2021

I have added the characterization of Quillen equivalences in the case that the right adjoint creates weak equivalences, here.

- Discussion Type
- discussion topicGrothendieck fibration
- Category Latest Changes
- Started by Urs
- Comments 23
- Last comment by Hurkyl
- Last Active Jan 13th 2021

I made the former entry "fibered category" instead a redirect to Grothendieck fibration. It didn't contain any addition information and was just mixing up links. I also made category fibered in groupoids redirect to Grothendieck fibration

I also edited the "Idea"-section at Grothendieck fibration slightly.

That big query box there ought to be eventually removed, and the important information established in the discussion filled into a proper subsection in its own right.

- Discussion Type
- discussion topicKan extension
- Category Latest Changes
- Started by Mike Shulman
- Comments 56
- Last comment by David_Corfield
- Last Active Jan 13th 2021

I think the line between the two types of Kan extension (weak versus pointwise) is drawn at the wrong place. Am I missing something?

- Discussion Type
- discussion topicisomonodromic deformation
- Category Latest Changes
- Started by zskoda
- Comments 1
- Last comment by zskoda
- Last Active Jan 13th 2021

- Discussion Type
- discussion topicgeneralized homology
- Category Latest Changes
- Started by Urs
- Comments 3
- Last comment by Urs
- Last Active Jan 13th 2021

for completeness, I have copied over and dualized the definitions and some of the properties of generalized cohomology to the entry

*generalized homology*.

- Discussion Type
- discussion topicBV-Laplacian
- Category Latest Changes
- Started by nLab edit announcer
- Comments 1
- Last comment by nLab edit announcer
- Last Active Jan 13th 2021

- Discussion Type
- discussion topicdomain theory
- Category Latest Changes
- Started by Urs
- Comments 1
- Last comment by Urs
- Last Active Jan 13th 2021

added pointer to:

- Tom de Jong, Martín Hötzel Escardó,
*Domain Theory in Constructive and Predicative Univalent Foundations*, in:*29th EACSL Annual Conference on Computer Science Logic*, CSL 2021, LIPIcs proceedings 183, 2021 (doi:10.4230/LIPIcs.CSL.2021.28, arXiv:2008.01422)

- Tom de Jong, Martín Hötzel Escardó,

- Discussion Type
- discussion topicMartín Escardó
- Category Latest Changes
- Started by David_Corfield
- Comments 2
- Last comment by Urs
- Last Active Jan 13th 2021

Added an article

- Martín Escardó and Paulo Oliva,
*Selection Functions, Bar Recursion, and Backward Induction*, (pdf)

- Martín Escardó and Paulo Oliva,

- Discussion Type
- discussion topicTom de Jong
- Category Latest Changes
- Started by Urs
- Comments 1
- Last comment by Urs
- Last Active Jan 13th 2021

brief

`category:people`

-entry for hyperlinking references at*domain theory*and*mathematics presented in HoTT*

- Discussion Type
- discussion topiccompactly generated (∞,1)-category
- Category Latest Changes
- Started by Hurkyl
- Comments 1
- Last comment by Hurkyl
- Last Active Jan 13th 2021

- Discussion Type
- discussion topicsequential spectrum
- Category Latest Changes
- Started by Urs
- Comments 12
- Last comment by Urs
- Last Active Jan 13th 2021

added some basics to

*sequential spectrum*: definition, $sSet^{\ast/}$-enrichment, statement of equivalence to $sSet^{\ast/}$-enriched functors on standard spheres and of Quillen equivalence to excisive $sSet^{\ast/}$-functors on $sSet^{\ast/}_{fin}$.(This is a digest of more detailed discussion that I am typing into

*model structure for excisive functors*.)

- Discussion Type
- discussion topicfunctorial field theory
- Category Latest Changes
- Started by Urs
- Comments 8
- Last comment by Dmitri Pavlov
- Last Active Jan 13th 2021

I am beginning to give the entry

*FQFT*a comprehensive*Exposition and Introduction*section.So far I have filled some genuine content into the first subsection

*Quantum mechanics in Schrödinger picture*.But I have to quit now. This isn’t even proof-read yet. So don’t look at it unless you feel more in editing-mood than in pure-reading-mood.

- Discussion Type
- discussion topicAQFT on curved spacetimes
- Category Latest Changes
- Started by Urs
- Comments 6
- Last comment by Urs
- Last Active Jan 12th 2021

- Discussion Type
- discussion topiceffective quantum field theory
- Category Latest Changes
- Started by Urs
- Comments 17
- Last comment by Urs
- Last Active Jan 12th 2021

at effective quantum field theory I have started writing an Idea-section and added more reference

- Discussion Type
- discussion topicLarry Smith
- Category Latest Changes
- Started by Urs
- Comments 1
- Last comment by Urs
- Last Active Jan 12th 2021

brief

`category:people`

-entry for hyperlinking references at*Eilenberg-Moore spectral sequence*and*Todd class*

- Discussion Type
- discussion topicRod M. Burstall
- Category Latest Changes
- Started by Tim_Porter
- Comments 1
- Last comment by Tim_Porter
- Last Active Jan 12th 2021

- Discussion Type
- discussion topicTuring machine
- Category Latest Changes
- Started by nLab edit announcer
- Comments 2
- Last comment by DavidRoberts
- Last Active Jan 11th 2021

- Discussion Type
- discussion topicMOFr
- Category Latest Changes
- Started by Urs
- Comments 1
- Last comment by Urs
- Last Active Jan 11th 2021

- Discussion Type
- discussion topicMU
- Category Latest Changes
- Started by Urs
- Comments 5
- Last comment by Dmitri Pavlov
- Last Active Jan 11th 2021

added these pointers:

Victor Buchstaber,

*The Chern–Dold character in cobordisms. I*,Russian original: Mat. Sb. (N.S.), 1970 Volume 83(125), Number 4(12), Pages 575–595 (mathnet:3530)

English translation: Mathematics of the USSR-Sbornik, Volume 12, Number 4, AMS 1970 (doi:10.1070/SM1970v012n04ABEH000939)

Victor Buchstaber, A. P. Veselov,

*Chern-Dold character in complex cobordisms and abelian varieties*(arXiv:2007.05782)

- Discussion Type
- discussion topicflavours of cobordism cohomology theories -- table
- Category Latest Changes
- Started by Urs
- Comments 15
- Last comment by Urs
- Last Active Jan 11th 2021

- Discussion Type
- discussion topicslice 2-category
- Category Latest Changes
- Started by Mike Shulman
- Comments 4
- Last comment by Mike Shulman
- Last Active Jan 11th 2021

Created slice 2-category.

- Discussion Type
- discussion topicMSO
- Category Latest Changes
- Started by Urs
- Comments 2
- Last comment by Urs
- Last Active Jan 11th 2021

a stub, for the moment just to fill the respective spot in

*flavours of cobordism cohomology theories – table*

- Discussion Type
- discussion topicpropagation of singularities theorem
- Category Latest Changes
- Started by Urs
- Comments 3
- Last comment by nLab edit announcer
- Last Active Jan 11th 2021

started something at

*propagation of singularities theorem*

- Discussion Type
- discussion topicDirac-Ramond operator
- Category Latest Changes
- Started by Urs
- Comments 12
- Last comment by Urs
- Last Active Jan 11th 2021

I suppose with all the entries on Witten genus and related what was missing was an entry titled

*Dirac-Ramond operator*. So I created one and filled in a bare minimum.

- Discussion Type
- discussion topicsupersymmetry
- Category Latest Changes
- Started by Urs
- Comments 47
- Last comment by Urs
- Last Active Jan 11th 2021

I’ll be working a bit on supersymmetry.

Zoran, you had once left two query boxes there with complaints. The second one is after this bit of the original entry (this will change any minute now)

The theory of supergravity is, as a classical field theory, an action functional on functions on a supermanifold $X$ which is invariant under the super-diffeomorphism group of $X$.

where you say

Zoran: action functional is on paths, even paths in infinitedimensional space, but not on point-functions.

I think you got something mixed up here. If $X$ is spacetime, a field on $X$

*is*the “path” that you want to see. The statement as given is correct, but I’ll try to expand on it.The second complaint is after where the original entry said

many models that suggest that the familiar symmetry of various action functionals should be enhanced to a supersymmetry in order to more properly describe fundamental physics.

You wrote:

This is doubtful and speculative. There are many models which have supersymmetry which is useful in their theoretical analysis, but the same models can be treated in formalisms not knowing about supersymmetry. Wheather the fundamental physics needs a model which has nontrivial supersymmetry is a speculative statement, and I disagree with equating theoretical physics with one direction in “fundamental physics”. I do not understand how can a model suggest supersymmetry; it is rather experimental evidence or problems with nonsupersymmetric models. Also one should distinguish the supersymmetry at the level of Lagrangean and the supersymmetry which holds only for each solution of the equation of motion.

I’ll rephrase the original statement to something less optimistic, but i do think that supersymmetry is suggsted more by looking at the formal nature of models than by lookin at the nature of nature. If you have a gauge theory for some Lie algebra (gravity, Poincaré Lie algebra) and the super extension of the Lie algebra has an interesting classification theory (the super Poincar´ algebra) then it is more th formalist in us who tends to feel compelled to investigate this than the phenomenologist. Supersymmetry is studied so much because it looks compelling on paper. Not because we have compelling phenomenological evidence. On the contrary.

So, if you don’t mind, I will remove both your query boxes and slightly polish the entry. Let’s have any further discussion here.

- Discussion Type
- discussion topicsuper Yang-Mills theory
- Category Latest Changes
- Started by Urs
- Comments 3
- Last comment by Urs
- Last Active Jan 11th 2021

finally created a stub for super Yang-Mills theory

- Discussion Type
- discussion topicJohn Strathdee
- Category Latest Changes
- Started by Urs
- Comments 1
- Last comment by Urs
- Last Active Jan 11th 2021

brief

`category:people`

-entry for hyperlinking references at*supersymetry*and*superspace*

- Discussion Type
- discussion topicsuperspace
- Category Latest Changes
- Started by Urs
- Comments 1
- Last comment by Urs
- Last Active Jan 11th 2021

completed publication data for:

- Abdus Salam, John Strathdee,
*Superfields and Fermi-Bose symmetry*, Physical Review D11, 1521-1535 (1975) (doi:10.1142/9789812795915_0051)

- Abdus Salam, John Strathdee,

- Discussion Type
- discussion topicstable cohomotopy
- Category Latest Changes
- Started by Urs
- Comments 20
- Last comment by Urs
- Last Active Jan 11th 2021