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- Discussion Type
- discussion topichigher curvature corrections to D=11 supergravity -- references
- Category Latest Changes
- Started by Urs
- Comments 7
- Last comment by Urs
- Last Active Mar 16th 2024

a bare list of references, previously coded both at

*D=11 supergravity*and at*higher curvature correction*, now extracted here to be`!include`

-ed back there, for ease of synchronizing

- Discussion Type
- discussion topicRichard Grimm
- Category Latest Changes
- Started by Urs
- Comments 1
- Last comment by Urs
- Last Active Mar 16th 2024

- Discussion Type
- discussion topicfiltered colimit
- Category Latest Changes
- Started by Urs
- Comments 0
- Last comment by yahado4
- Last Active Mar 15th 2024

- Discussion Type
- discussion topicstring scattering amplitude
- Category Latest Changes
- Started by Urs
- Comments 10
- Last comment by Urs
- Last Active Mar 15th 2024

added a bunch of pointers to the literature (with brief comments) at

*string scattering amplitude*.Also added a corresponding paragraph at

*effective field theory*.(this is still in reaction to that MO discussion, specifically to the question here)

- Discussion Type
- discussion topicharmonic differential form
- Category Latest Changes
- Started by Urs
- Comments 2
- Last comment by DavidRoberts
- Last Active Mar 15th 2024

added pointer to:

- Georges de Rham, Chapter V of:
*Differentiable Manifolds – Forms, Currents, Harmonic Forms*, Grundlehren**266**, Springer (1984) [doi:10.1007/978-3-642-61752-2]

- Georges de Rham, Chapter V of:

- Discussion Type
- discussion topicweakly Lindelöf spaces with countably locally finite base are second countable
- Category Latest Changes
- Started by Daniel Luckhardt
- Comments 6
- Last comment by Patrick Rabau
- Last Active Mar 14th 2024

Created in context of topology - global countability axioms

- Discussion Type
- discussion topicBSU(n)
- Category Latest Changes
- Started by Samuel Adrian Antz
- Comments 1
- Last comment by Samuel Adrian Antz
- Last Active Mar 14th 2024

Created page for BSU(n), the classifying space of the special unitary group SU(n). (See discussion on Stiefel-Whitney class.) There’s still a lot to add, but I will do so in the future. (The english and german Wikipedia page are now also available.)

- Discussion Type
- discussion topicBSO(n)
- Category Latest Changes
- Started by Samuel Adrian Antz
- Comments 1
- Last comment by Samuel Adrian Antz
- Last Active Mar 14th 2024

Created page for BSO(n), the classifying space of the special orthogonal group SO(n). (See discussion on Stiefel-Whitney class.) There’s still a lot to add, but I will do so in the future. (The english and german Wikipedia page are now also available.)

- Discussion Type
- discussion topicternary frame
- Category Latest Changes
- Started by Mike Shulman
- Comments 14
- Last comment by Urs
- Last Active Mar 14th 2024

Created ternary frame, a class of models for substructural logic which are basically obtained from Day convolution for promonoidal posets. Presumably people who know things know this, but in a few minutes of looking I haven’t found anyone mentioning it. Girard’s “phase space” semantics for linear logic (no relation to phase spaces of physics) are just the special case of regarding a monoidal category as a promonoidal one.

- Discussion Type
- discussion topicbraid group statistics
- Category Latest Changes
- Started by Urs
- Comments 23
- Last comment by Urs
- Last Active Mar 14th 2024

stub for

*braid group statistics*(again, for the moment mainly in order to record a reference)

- Discussion Type
- discussion topicMarcia E. Knutt-Wehlau
- Category Latest Changes
- Started by Urs
- Comments 1
- Last comment by Urs
- Last Active Mar 14th 2024

- Discussion Type
- discussion topicfinal (infinity,1)-functor
- Category Latest Changes
- Started by nLab edit announcer
- Comments 18
- Last comment by Urs
- Last Active Mar 14th 2024

- Discussion Type
- discussion topicequifibration
- Category Latest Changes
- Started by Richard Williamson
- Comments 16
- Last comment by Mike Shulman
- Last Active Mar 13th 2024

Creating the page, linked to from isofibration currently. Not yet finished, but contains so far the definition and some remarks on expressing it as a lifting condition. In a later edit, I will discuss the second condition, and remark on viewing Lack fibrations as ’Hurewicz fibrations’.

- Discussion Type
- discussion topicS-duality
- Category Latest Changes
- Started by Urs
- Comments 10
- Last comment by perezl.alonso
- Last Active Mar 13th 2024

stub for S-duality – disambiguation and then the physics meaning

- Discussion Type
- discussion topicIan N. McArthur
- Category Latest Changes
- Started by Urs
- Comments 1
- Last comment by Urs
- Last Active Mar 13th 2024

- Discussion Type
- discussion topicRiemann normal coordinates
- Category Latest Changes
- Started by Urs
- Comments 1
- Last comment by Urs
- Last Active Mar 13th 2024

- Discussion Type
- discussion topicessentially algebraic (infinity,1)-theory
- Category Latest Changes
- Started by Hurkyl
- Comments 1
- Last comment by Hurkyl
- Last Active Mar 12th 2024

- Discussion Type
- discussion topicessentially algebraic theory
- Category Latest Changes
- Started by Urs
- Comments 11
- Last comment by varkor
- Last Active Mar 12th 2024

added references to

*essentially algebraic theory*. Also equipped the text with a few more hyperlinks.

- Discussion Type
- discussion topictorsion of a Cartan connection
- Category Latest Changes
- Started by Urs
- Comments 2
- Last comment by Urs
- Last Active Mar 12th 2024

gave

*torsion of a Cartan connection*its own entry, and cross-linked a bit.

- Discussion Type
- discussion topictensor category
- Category Latest Changes
- Started by Urs
- Comments 6
- Last comment by perezl.alonso
- Last Active Mar 12th 2024

added this pointer:

- Damien Calaque, Pavel Etingof,
*Lectures on tensor categories*, IRMA Lectures in Mathematics and Theoretical Physics 12, 1-38 (2008) (arXiv:math/0401246)

- Damien Calaque, Pavel Etingof,

- Discussion Type
- discussion topicBanach-Tarski paradox
- Category Latest Changes
- Started by Urs
- Comments 4
- Last comment by nLab edit announcer
- Last Active Mar 12th 2024

a stub, for the moment just so as to record pointer to Simpson 12 where “resolution of the paradox” is claimed to be achieved simply by passing from topological spaces to locales

- Discussion Type
- discussion topiccovariant derivative
- Category Latest Changes
- Started by Urs
- Comments 6
- Last comment by Urs
- Last Active Mar 12th 2024

wrote a definition and short discussion of covariant derivative in the spirit of oo-Chern-Weil theory

- Discussion Type
- discussion topicG-crossed braided fusion category
- Category Latest Changes
- Started by nLab edit announcer
- Comments 4
- Last comment by Urs
- Last Active Mar 12th 2024

- Discussion Type
- discussion topicCorey Jones
- Category Latest Changes
- Started by Urs
- Comments 1
- Last comment by Urs
- Last Active Mar 12th 2024

- Discussion Type
- discussion topicShawn X. Cui
- Category Latest Changes
- Started by Urs
- Comments 1
- Last comment by Urs
- Last Active Mar 12th 2024

- Discussion Type
- discussion topicextended functorial field theory
- Category Latest Changes
- Started by Urs
- Comments 10
- Last comment by Urs
- Last Active Mar 12th 2024

added pointer to:

- Lukas Müller,
*Extended Functorial Field Theories and Anomalies in Quantum Field Theories*(arXiv:2003.08217)

- Lukas Müller,

- Discussion Type
- discussion topictwisted arrow (∞,1)-category
- Category Latest Changes
- Started by Hurkyl
- Comments 11
- Last comment by Hurkyl
- Last Active Mar 12th 2024

Created an entry for this.

I’ve adopted the existing convention at nLab in the definition of $Tw(C)$ (which is also the definition I prefer).

Since the opposite convention is used a lot (e.g. by Lurie), I’ve decided it was worth giving it notation, the relation between the versions, and citing results in both forms. Since I didn’t have any better ideas, I’ve settled on $\overline{Tw}(C)$.

- Discussion Type
- discussion topicAlexander W. Smith
- Category Latest Changes
- Started by Urs
- Comments 1
- Last comment by Urs
- Last Active Mar 12th 2024

- Discussion Type
- discussion topicinfinity-category
- Category Latest Changes
- Started by adeelkh
- Comments 12
- Last comment by Urs
- Last Active Mar 12th 2024

I just added a link to Lurie's "What is...?" paper.

- Discussion Type
- discussion topicalgebraic number theory
- Category Latest Changes
- Started by Urs
- Comments 2
- Last comment by Urs
- Last Active Mar 12th 2024

added more publication data and links to:

- J. W. S. Cassels, Albrecht Fröhlich (eds.),
*Algebraic number theory*, Acad. Press 1967, with many reprints; Fröhlich, Cassels, Birch, Atiyah, Wall, Gruenberg, Serre, Tate, Heilbronn, Rouqette, Kneser, Hasse, Swinerton-Dyer, Hoechsmann, systematic lecture notes from the instructional conference at Univ. of Sussex, Brighton, Sep. 1-17, 1965 (ISBN:9780950273426, pdf, errata pdf by Kevin Buzzard)

also, I have fixed the order of the editor’s names

- J. W. S. Cassels, Albrecht Fröhlich (eds.),

- Discussion Type
- discussion topicZach Goldthorpe
- Category Latest Changes
- Started by Urs
- Comments 2
- Last comment by David_Corfield
- Last Active Mar 12th 2024

- Discussion Type
- discussion topicconductor
- Category Latest Changes
- Started by David_Corfield
- Comments 1
- Last comment by David_Corfield
- Last Active Mar 12th 2024

- Discussion Type
- discussion topicBU(n)
- Category Latest Changes
- Started by Samuel Adrian Antz
- Comments 5
- Last comment by Samuel Adrian Antz
- Last Active Mar 12th 2024

Created page for BU(n), the classifying space of the unitary group U(n). (See discussion on Stiefel-Whitney class.) There is still a lot to add though.

- Discussion Type
- discussion topicBO(n)
- Category Latest Changes
- Started by Samuel Adrian Antz
- Comments 7
- Last comment by Samuel Adrian Antz
- Last Active Mar 12th 2024

Created page for BO(n), the classifying space of the orthogonal group O(n). (See discussion on Stiefel-Whitney class.) There is still a lot to add though.

- Discussion Type
- discussion topicHandbook of Quantum Gravity
- Category Latest Changes
- Started by Urs
- Comments 16
- Last comment by Urs
- Last Active Mar 12th 2024

- Discussion Type
- discussion topicS-matrix
- Category Latest Changes
- Started by Urs
- Comments 57
- Last comment by Urs
- Last Active Mar 12th 2024

added to

*S-matrix*a useful historical comment by Ron Maimon (see there for citation)

- Discussion Type
- discussion topicweight systems on chord diagrams in physics
- Category Latest Changes
- Started by Urs
- Comments 14
- Last comment by Urs
- Last Active Mar 12th 2024

- Discussion Type
- discussion topicreal projective space
- Category Latest Changes
- Started by Urs
- Comments 14
- Last comment by Samuel Adrian Antz
- Last Active Mar 12th 2024

added a quick note on the CW-structure on real projective space: here.

- Discussion Type
- discussion topicevents of interest for the working category theorist
- Category Latest Changes
- Started by Urs
- Comments 13
- Last comment by Sam Staton
- Last Active Mar 11th 2024

Following discussion here,

this is a page to be used for announcements of events (conferences, workshops, …) on category theory.

- Discussion Type
- discussion topicformalized libraries of homotopy type theory
- Category Latest Changes
- Started by Mike Shulman
- Comments 8
- Last comment by Mike Shulman
- Last Active Mar 11th 2024

- Discussion Type
- discussion topicBanach space
- Category Latest Changes
- Started by Mark Meckes
- Comments 35
- Last comment by TobyBartels
- Last Active Mar 11th 2024

I’ve expanded the section on morphisms in Banach space, because the new page on isomorphism classes of Banach spaces refers to a different notion of isomorphism than what the Banach space page previously called the “usual” notion of isomorphism. (The issue is that what’s usual seems to be different for analysts and category theorists.)

- Discussion Type
- discussion topicWendy Lowen
- Category Latest Changes
- Started by zskoda
- Comments 2
- Last comment by Tim_Porter
- Last Active Mar 11th 2024

- 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 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)