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2-category 2-category-theory abelian-categories adjoint algebra algebraic algebraic-geometry algebraic-topology analysis analytic-geometry arithmetic arithmetic-geometry bundle bundles calculus categories category category-theory chern-weil-theory cohesion cohesive-homotopy-type-theory cohomology colimits combinatorics complex-geometry computable-mathematics computer-science constructive constructive-mathematics cosmology definitions deformation-theory descent diagrams differential differential-cohomology differential-equations differential-geometry digraphs duality elliptic-cohomology enriched fibration finite foundations functional-analysis functor galois-theory gauge-theory gebra geometric-quantization geometry graph graphs gravity 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 limit limits linear linear-algebra locale localization logic manifolds mathematics measure-theory modal-logic model model-category-theory monads monoidal monoidal-category-theory morphism motives motivic-cohomology multicategories nonassociative noncommutative noncommutative-geometry number-theory of operads operator operator-algebra order-theory pages 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 stack string string-theory superalgebra supergeometry svg symplectic-geometry synthetic-differential-geometry terminology theory topology topos topos-theory type type-theory universal variational-calculus

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- Discussion Type
- discussion topicfunctoriality of categories of presheaves
- Category Latest Changes
- Started by anuyts
- Comments 1
- Last comment by anuyts
- Last Active 2 hours ago

- Discussion Type
- discussion topicPontrjagin-Thom collapse map
- Category Latest Changes
- Started by Urs
- Comments 3
- Last comment by Urs
- Last Active 5 hours ago

added to the Idea-section (here) the description of PT-collapse as the function that assigns “asymptotic distance form the submanifold”, an illustrating graphics, and a comment that this represents the Cohomotopy charge of the submanifold

- Discussion Type
- discussion topicstring field theory
- Category Latest Changes
- Started by Urs
- Comments 18
- Last comment by Urs
- Last Active 5 hours ago

I have started adding references to

*string field theory*, in particular those by Jim Stasheff et al. on the role of L-infinity algebra and A-infinity algebra. Maybe I find time later to add more details.

- Discussion Type
- discussion topicframed manifold
- Category Latest Changes
- Started by Urs
- Comments 7
- Last comment by David_Corfield
- Last Active 9 hours ago

added a bit to

*framed manifold*

- Discussion Type
- discussion topicDuff interview at M-Theory-Mathematics 2020
- Category Latest Changes
- Started by Urs
- Comments 10
- Last comment by Urs
- Last Active 9 hours ago

- Discussion Type
- discussion topicStarobinsky model of cosmic inflation
- Category Latest Changes
- Started by Urs
- Comments 15
- Last comment by Urs
- Last Active 15 hours ago

- Discussion Type
- discussion topicPaolo Perrone
- Category Latest Changes
- Started by PaoloPerrone
- Comments 2
- Last comment by Urs
- Last Active 15 hours ago

- Discussion Type
- discussion topicstrong monad
- Category Latest Changes
- Started by Sam Staton
- Comments 12
- Last comment by PaoloPerrone
- Last Active 15 hours ago

- Discussion Type
- discussion topicuniversal Vassiliev invariant
- Category Latest Changes
- Started by Urs
- Comments 7
- Last comment by Urs
- Last Active 15 hours ago

- Discussion Type
- discussion topicMarkov category
- Category Latest Changes
- Started by PaoloPerrone
- Comments 1
- Last comment by PaoloPerrone
- Last Active 21 hours ago

- Discussion Type
- discussion topicgroup
- Category Latest Changes
- Started by Urs
- Comments 5
- Last comment by Todd_Trimble
- Last Active 21 hours ago

reformatted the entry group a little, expanded the Examples-section a little and then pasted in the group-related “counterexamples” from counterexamples in algebra. Mainly to indicate how I think this latter entry should eventually be used to improve the entries that it refers to.

- Discussion Type
- discussion topicM-theory
- Category Latest Changes
- Started by David_Corfield
- Comments 15
- Last comment by Urs
- Last Active 1 day ago

A stub for M-theory. What’s supposed to be so mysterious about it? Is it that people don’t even know what form it would take?

- Discussion Type
- discussion topicCantor-Schroeder-Bernstein theorem
- Category Latest Changes
- Started by Mike Shulman
- Comments 6
- Last comment by DavidRoberts
- Last Active 1 day ago

- Discussion Type
- discussion topichorizontal chord diagram
- Category Latest Changes
- Started by Urs
- Comments 13
- Last comment by Urs
- Last Active 1 day ago

- Discussion Type
- discussion topicflavour anomaly
- Category Latest Changes
- Started by Urs
- Comments 104
- Last comment by Urs
- Last Active 1 day ago

- Discussion Type
- discussion topichydrogen line
- Category Latest Changes
- Started by Urs
- Comments 7
- Last comment by Urs
- Last Active 1 day ago

Detection of the 21cm hydrogen absorption line expected in the CMB has been claimed now. Such a detection is thought to have implications for observational cosmology comparable in relevance to those of the recent gravitational wave detection. I have collected some original articles and reviews here in an otherwise empty entry

*hydrogen line*

- Discussion Type
- discussion topicconvex function
- Category Latest Changes
- Started by Todd_Trimble
- Comments 4
- Last comment by TobyBartels
- Last Active 2 days ago

Expanded the formerly stubby article convex function, giving examples, properties, etc.

- Discussion Type
- discussion topicbosonic M-theory
- Category Latest Changes
- Started by David_Corfield
- Comments 9
- Last comment by Urs
- Last Active 2 days ago

- Discussion Type
- discussion topicJackiw-Teitelboim gravity
- Category Latest Changes
- Started by Urs
- Comments 7
- Last comment by Urs
- Last Active 2 days ago

- Discussion Type
- discussion topicEntropy
- Category Latest Changes
- Started by TobyBartels
- Comments 45
- Last comment by DavidRoberts
- Last Active 2 days ago

I have written a disordered article lacking information. No, wait! I mean, I have written an article on a measure of disorder and lack of information: entropy.

This is from a very mathematical perspective, but I have also tried to indicate how this connects to the physical notion of entropy. (This is something that I would like to understand better!)

- Discussion Type
- discussion topicSYK-model and AdS2-CFT1 -- references
- Category Latest Changes
- Started by Urs
- Comments 3
- Last comment by Urs
- Last Active 2 days ago

- Discussion Type
- discussion topicopen/closed string duality
- Category Latest Changes
- Started by nLab edit announcer
- Comments 6
- Last comment by Urs
- Last Active 3 days ago

- Discussion Type
- discussion topicprototype CLF
- Category Latest Changes
- Started by atmacen
- Comments 46
- Last comment by atmacen
- Last Active 3 days ago

- Discussion Type
- discussion topiclarge 1/N limit
- Category Latest Changes
- Started by Urs
- Comments 8
- Last comment by Urs
- Last Active 4 days ago

- Discussion Type
- discussion topicfour-colour theorem
- Category Latest Changes
- Started by Urs
- Comments 1
- Last comment by Urs
- Last Active 4 days ago

added this pointer (hat tip to David C. here):

On the logical equivalence between the four-colour theorem and a statement about transition from the small N limit to the large N limit for Lie algebra weight systems on Jacobi diagrams via the ’t Hooft double line construction:

- Dror Bar-Natan,
*Lie Algebras and the Four Color Theorem*, Combinatorica 17-1(1997) 43–52 (arXiv:q-alg/9606016, doi:10.1007/BF01196130)

- Dror Bar-Natan,

- Discussion Type
- discussion topicAdS-QCD correspondence
- Category Latest Changes
- Started by Urs
- Comments 31
- Last comment by Urs
- Last Active 4 days ago

- Discussion Type
- discussion topiccolor charge
- Category Latest Changes
- Started by Urs
- Comments 2
- Last comment by Urs
- Last Active 4 days ago

- Discussion Type
- discussion topicQCD and strongly coupled gauge theories - challenges and perspectives
- Category Latest Changes
- Started by Urs
- Comments 1
- Last comment by Urs
- Last Active 4 days ago

- Discussion Type
- discussion topicpion
- Category Latest Changes
- Started by Urs
- Comments 1
- Last comment by Urs
- Last Active 4 days ago

added pointer to today’s

- Domenec Espriu, Alisa Katanaeva,
*Effects of bulk symmetry breaking on AdS/QCD predictions*(arXiv:2001.08723)

- Domenec Espriu, Alisa Katanaeva,

- Discussion Type
- discussion topicmonads of probability, measures, and valuations
- Category Latest Changes
- Started by PaoloPerrone
- Comments 7
- Last comment by PaoloPerrone
- Last Active 5 days ago