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- Discussion Type
- discussion topicIvan Mirkovic > history
- Category Latest Changes
- Started by Urs
- Comments 2
- Last comment by zskoda
- Last Active Mar 10th 2024

have cleared this page and merged its content into

*Ivan Mirković*

- Discussion Type
- discussion topicDragon's theorem
- Category Latest Changes
- Started by Urs
- Comments 1
- Last comment by Urs
- Last Active Mar 10th 2024

- Discussion Type
- discussion topicentanglement island proposal for black hole paradox -- references
- Category Latest Changes
- Started by Urs
- Comments 3
- Last comment by Urs
- Last Active Mar 10th 2024

this is a bare list of references, meant to be

`!include`

-ed into the relevant References-sections at*black hole information paradox*and*Bekenstein-Hawkind entropy*

- Discussion Type
- discussion topicThomas Schmitt
- Category Latest Changes
- Started by Urs
- Comments 1
- Last comment by Urs
- Last Active Mar 10th 2024

- Discussion Type
- discussion topicsupergravity
- Category Latest Changes
- Started by Urs
- Comments 16
- Last comment by Urs
- Last Active Mar 10th 2024

created supergravity

so far just an "Idea" section and a link to D'Auria-Fre formulation of supergravity (which i am busy working on)

- Discussion Type
- discussion topicsupersymmetry
- Category Latest Changes
- Started by Urs
- Comments 54
- Last comment by Urs
- Last Active Mar 10th 2024

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 topicGauge Field Theory and Complex Geometry
- Category Latest Changes
- Started by Urs
- Comments 1
- Last comment by Urs
- Last Active Mar 10th 2024

- Discussion Type
- discussion topicNew Dimensions in Geometry
- Category Latest Changes
- Started by Urs
- Comments 1
- Last comment by Urs
- Last Active Mar 10th 2024

added publication data (notably the doi:10.1007/BFb0084585) and some formatting

- Discussion Type
- discussion topicquantum gravity
- Category Latest Changes
- Started by Urs
- Comments 17
- Last comment by Urs
- Last Active Mar 10th 2024

in order to satisfy links, but maybe really in procrastination of other duties, I wrote something at quantum gravity

- Discussion Type
- discussion topicD=12 supergravity
- Category Latest Changes
- Started by David_Corfield
- Comments 26
- Last comment by perezl.alonso
- Last Active Mar 9th 2024

Started 12-dimensional supergravity following some discussion with Urs.

- Discussion Type
- discussion topicmonoidal monad
- Category Latest Changes
- Started by Todd_Trimble
- Comments 20
- Last comment by ncfavier
- Last Active Mar 9th 2024

Started an article on monoidal monad. An earlier redirect had sent it over to Hopf monad which is something that Zoran was working on, but I think it deserves an article to itself, with discussion of the relation to commutative monads, etc. (which I have started).

- Discussion Type
- discussion topictransfinite composition
- Category Latest Changes
- Started by Urs
- Comments 9
- Last comment by Manuel Araújo
- Last Active Mar 9th 2024

added illustrating diagram to transfinite composition

I also renamed the resulting composite morphism into . Hope I did this consistently.

- Discussion Type
- discussion topicMichel Rausch de Traubenberg
- Category Latest Changes
- Started by Urs
- Comments 1
- Last comment by Urs
- Last Active Mar 9th 2024

- Discussion Type
- discussion topicframed bicategory
- Category Latest Changes
- Started by Urs
- Comments 6
- Last comment by varkor
- Last Active Mar 9th 2024

created quick stub for framed bicategory

but my machine's battery will die any second now...

- Discussion Type
- discussion topicvirtual double category
- Category Latest Changes
- Started by maxsnew
- Comments 13
- Last comment by varkor
- Last Active Mar 9th 2024

I added some examples of virtual double categories that do not have composites described in Crutwell-Shulman.

- Discussion Type
- discussion topicIvan Mirković
- Category Latest Changes
- Started by Urs
- Comments 3
- Last comment by Urs
- Last Active Mar 9th 2024

- Discussion Type
- discussion topiccanonical model structure on 2-categories
- Category Latest Changes
- Started by Richard Williamson
- Comments 5
- Last comment by Mike Shulman
- Last Active Mar 8th 2024

- Discussion Type
- discussion topicidempotent monoidal functor
- Category Latest Changes
- Started by ncfavier
- Comments 1
- Last comment by ncfavier
- Last Active Mar 8th 2024

Added idempotent monoidal functor.

- Discussion Type
- discussion topicstrict initial object
- Category Latest Changes
- Started by Urs
- Comments 14
- Last comment by ncfavier
- Last Active Mar 8th 2024

split off

*strict initial object*from*initial object*(in order to be able to point to it directly from within proofs elsewhere)

- Discussion Type
- discussion topicGrothendieck fibration
- Category Latest Changes
- Started by Urs
- Comments 46
- Last comment by maxsnew
- Last Active Mar 8th 2024

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 topicpi-calculus
- Category Latest Changes
- Started by Victor Sannier
- Comments 10
- Last comment by Victor Sannier
- Last Active Mar 8th 2024

- Discussion Type
- discussion topicsupergroup
- Category Latest Changes
- Started by Urs
- Comments 3
- Last comment by Urs
- Last Active Mar 8th 2024

Added the Yoneda-embedding way to talk about group objects and hence supergroups.

- Discussion Type
- discussion topicintegration over supermanifolds
- Category Latest Changes
- Started by Urs
- Comments 5
- Last comment by Urs
- Last Active Mar 8th 2024

added pointer to Belopolsky97b etc., regarding “picture number” induced by a choice of integral top-forms.

- Discussion Type
- discussion topicsuper algebra
- Category Latest Changes
- Started by Urs
- Comments 3
- Last comment by Urs
- Last Active Mar 8th 2024

Somebody from the technical team kindly alerted me that we have a full

`.mov`

copy of the video recording of Kapranov 2013 sitting on the nLab server – which is strange (but also lucky), does anyone know/remember how this came to be?In trying to understand what’s going on, I noticed that the relevant YouTube link at Kapranov 2013 had died (“private”) as had my original video link from comment #5 in the original thread. Also the links to the hosting conference had meanwhile rotted away.

I have now

recovered the conference links via the WaybackMachine,

added the link to our local copy of the video recording

and am also uploading the video to YouTube.

Am propagating these edits also to other entries where Kapranov’s talk is referenced, such as at

*Mikhail Kapranov*and at*spectral super-scheme*.

- Discussion Type
- discussion topicQuantum Fields and Strings
- Category Latest Changes
- Started by Urs
- Comments 3
- Last comment by Urs
- Last Active Mar 8th 2024

added ISBN:978-0-8218-2014-8

- Discussion Type
- discussion topiclocally cartesian (infinity,1)-category
- Category Latest Changes
- Started by nLab edit announcer
- Comments 1
- Last comment by nLab edit announcer
- Last Active Mar 8th 2024

- Discussion Type
- discussion topiclax monoidal category
- Category Latest Changes
- Started by Mike Shulman
- Comments 14
- Last comment by varkor
- Last Active Mar 7th 2024

- Discussion Type
- discussion topicbosonization
- Category Latest Changes
- Started by perezl.alonso
- Comments 1
- Last comment by perezl.alonso
- Last Active Mar 7th 2024

pointer

- Philip Boyle Smith, Yunqin Zheng.
*Backfiring Bosonisation*(2024). (arXiv:2403.03953).

- Philip Boyle Smith, Yunqin Zheng.

- Discussion Type
- discussion topicLars Brink
- Category Latest Changes
- Started by Urs
- Comments 2
- Last comment by Urs
- Last Active Mar 7th 2024

added pointer to this obituary:

- Hermann Nicolai:
*Lars Brink 1943–2022*, CernCourier (1 Mar 2023):

- Hermann Nicolai:

- Discussion Type
- discussion topiccartesian product
- Category Latest Changes
- Started by Todd_Trimble
- Comments 5
- Last comment by varkor
- Last Active Mar 6th 2024

- Discussion Type
- discussion topicfusion 2-category
- Category Latest Changes
- Started by Urs
- Comments 3
- Last comment by perezl.alonso
- Last Active Mar 6th 2024

A stub, for the moment just to have a place for recording a couple of references (which were previously at

*fusion category*.

- Discussion Type
- discussion topicspin-statistics theorem
- Category Latest Changes
- Started by Urs
- Comments 19
- Last comment by nLab edit announcer
- Last Active Mar 6th 2024

stub for spin-statistics theorem. Just recording a first few references so far.

- Discussion Type
- discussion topicbiproduct
- Category Latest Changes
- Started by Colin Tan
- Comments 24
- Last comment by J-B Vienney
- Last Active Mar 6th 2024

- Discussion Type
- discussion topicdirected homotopy type theory
- Category Latest Changes
- Started by Urs
- Comments 41
- Last comment by ncfavier
- Last Active Mar 5th 2024

created directed homotopy type theory

- Discussion Type
- discussion topictiny object
- Category Latest Changes
- Started by varkor
- Comments 5
- Last comment by maxsnew
- Last Active Mar 5th 2024

- Discussion Type
- discussion topicweak bialgebra
- Category Latest Changes
- Started by zskoda
- Comments 5
- Last comment by perezl.alonso
- Last Active Mar 5th 2024

To support mentioning weak wreath product in a parallel discussion with Urs, I created a stub for weak bialgebra with redirect weak Hopf algebra.

- Discussion Type
- discussion topicquantum mechanics
- Category Latest Changes
- Started by Urs
- Comments 31
- Last comment by Urs
- Last Active Mar 5th 2024

in analogy to what I just did at classical mechanics, I have now added some basic but central content to quantum mechanics:

Quantum mechanical systems

States and observables

Spaces of states

Flows and time evolution

Still incomplete and rough. But I have to quit now.

- Discussion Type
- discussion topicoptic (in computer science)
- Category Latest Changes
- Started by David_Corfield
- Comments 10
- Last comment by BryceClarke
- Last Active Mar 5th 2024

- Discussion Type
- discussion topicHayder Salman
- Category Latest Changes
- Started by Urs
- Comments 1
- Last comment by Urs
- Last Active Mar 5th 2024

- Discussion Type
- discussion topicquantum phase transition
- Category Latest Changes
- Started by Urs
- Comments 2
- Last comment by Urs
- Last Active Mar 5th 2024

a stub, for the moment just to make some cross-links work (such as with topological order and topological entanglement entropy)

- Discussion Type
- discussion topiccomplete graph
- Category Latest Changes
- Started by nLab edit announcer
- Comments 2
- Last comment by Urs
- Last Active Mar 5th 2024

- Discussion Type
- discussion topicRarita-Schwinger field
- Category Latest Changes
- Started by Urs
- Comments 1
- Last comment by Urs
- Last Active Mar 5th 2024

added pointer to:

- Mauricio Valenzuela, Jorge Zanelli,
*The propagating modes of the massless Rarita–Schwinger system*[arXiv:2305.00106]

- Mauricio Valenzuela, Jorge Zanelli,

- Discussion Type
- discussion topicworldline formalism
- Category Latest Changes
- Started by Urs
- Comments 18
- Last comment by Urs
- Last Active Mar 5th 2024

created

*worldline formalism*to go with this Physics.SE answer

- Discussion Type
- discussion topicperfect infinity-stack
- Category Latest Changes
- Started by Urs
- Comments 2
- Last comment by Samuel Adrian Antz
- Last Active Mar 5th 2024

I expanded perfect infinity-stack a little. But this deserves further polishing and expanding.

- Discussion Type
- discussion topicclassifying space
- Category Latest Changes
- Started by Urs
- Comments 44
- Last comment by Samuel Adrian Antz
- Last Active Mar 4th 2024

I noticed that the entry classifying space is in bad shape. I have added a table of contents and tried to structure it slightly, but much more needs to be done here.

I have added a paragraph on standard classifying spaces for topological principal bundles via the geometric realization of the simplicial space associated to the given topological group.

In the section “For crossed complexes” there is material that had been provided by Ronnie Brown which needs to be harmonized with the existing Idea-section. It proposes something like a general axiomatics on the notion of “classifying space” more than giving details on the geometric realization of crossed complexes

- Discussion Type
- discussion topicquasi-Hopf algebra
- Category Latest Changes
- Started by Urs
- Comments 18
- Last comment by perezl.alonso
- Last Active Mar 4th 2024

The Idea-section at

*quasi-Hopf algebra*had been confused and wrong. I have removed it and written a new one.

- Discussion Type
- discussion topicgravitino
- Category Latest Changes
- Started by Urs
- Comments 2
- Last comment by Urs
- Last Active Mar 4th 2024

one more from Meissner & Nicolai, last week:

- Krzysztof A. Meissner, Hermann Nicolai,
*Evidence for a stable supermassive gravitino with charge $2/3$?*[arXiv:2303.09131]

- Krzysztof A. Meissner, Hermann Nicolai,

- Discussion Type
- discussion topicpromonoidal category
- Category Latest Changes
- Started by Mike Shulman
- Comments 20
- Last comment by varkor
- Last Active Mar 4th 2024

I moved the definition of promonoidal categories from Day convolution to promonoidal category, and expanded on it a bit.

- Discussion Type
- discussion topicrepresentable morphism
- Category Latest Changes
- Started by zskoda
- Comments 11
- Last comment by anuyts
- Last Active Mar 4th 2024

New entry representable morphism, in the sense of Grothendieck school. The notion is used at closed immersion of schemes where I just made some changes.

- Discussion Type
- discussion topicsuper Poincaré Lie algebra
- Category Latest Changes
- Started by perezl.alonso
- Comments 3
- Last comment by perezl.alonso
- Last Active Mar 4th 2024

- Discussion Type
- discussion topicdependent linear type theory
- Category Latest Changes
- Started by Urs
- Comments 92
- Last comment by Urs
- Last Active Mar 4th 2024

Following discussion in some other threads, I thought one should make it explicit and so I created an entry

Currently this contains some (hopefully) evident remarks of what “dependent linear type theory” reasonably should be at least, namely a hyperdoctrine with values in linear type theories.

The entry keeps saying “should”. I’d ask readers to please either point to previous proposals for what “linear dependent type theory” is/should be, or criticise or else further expand/refine what hopefully are the obvious definitions.

This is hopefully uncontroversial and should be regarded an obvious triviality. But it seems it might be one of those hidden trivialities which deserve to be highlighted a bit more. I am getting the impression that there is a big story hiding here.

Thanks for whatever input you might have.

- Discussion Type
- discussion topicjet bundle
- Category Latest Changes
- Started by Urs
- Comments 63
- Last comment by perezl.alonso
- Last Active Mar 3rd 2024

stub for jet bundle

- Discussion Type
- discussion topicnormed ring
- Category Latest Changes
- Started by Urs
- Comments 5
- Last comment by Urs
- Last Active Mar 3rd 2024

An edit to

*normed ring*is being discussed in another thread, here.

- Discussion Type
- discussion topicPoincaré-Weyl algebra
- Category Latest Changes
- Started by perezl.alonso
- Comments 1
- Last comment by perezl.alonso
- Last Active Mar 2nd 2024

- Discussion Type
- discussion topicYoshiaki Tanii
- Category Latest Changes
- Started by Urs
- Comments 1
- Last comment by Urs
- Last Active Mar 2nd 2024

- Discussion Type
- discussion topicpiecewise flat spacetime
- Category Latest Changes
- Started by Urs
- Comments 7
- Last comment by Urs
- Last Active Mar 2nd 2024

- Discussion Type
- discussion topicWheeler superspace
- Category Latest Changes
- Started by Urs
- Comments 3
- Last comment by Urs
- Last Active Mar 2nd 2024

- Discussion Type
- discussion topicspin connection
- Category Latest Changes
- Started by Urs
- Comments 3
- Last comment by Urs
- Last Active Mar 2nd 2024

added pointer to:

- Thanu Padmanabhan, §11.6 in:
*Gravitation – Foundations and Frontiers*, Cambridge University Press (2012) [doi:10.1017/CBO9780511807787, spire:852758, toc: pdf]

- Thanu Padmanabhan, §11.6 in:

- Discussion Type
- discussion topicCartan connection
- Category Latest Changes
- Started by Urs
- Comments 14
- Last comment by Urs
- Last Active Mar 2nd 2024

added to Cartan connection

definition

a standard reference

a standard example

- Discussion Type
- discussion topicsuper-Cartan geometry
- Category Latest Changes
- Started by David_Corfield
- Comments 33
- Last comment by Urs
- Last Active Mar 2nd 2024

I see super-Cartan geometry is taking shape. Will Clifford algebras make an appearance in the The super-Klein geometry: super-Minkowski spacetime section?

Is there a higher super-Cartan way of thinking about what is at 3-category of fermionic conformal nets, about the String 2-group and superstrings, as here about the spin group and fermions.