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- Discussion Type
- discussion topiccubical type theory
- Category Latest Changes
- Started by Urs
- Comments 11
- Last comment by spitters
- Last Active 7 days ago

started

*cubical type theory*using a comment by Jonathan Sterling

- Discussion Type
- discussion topicset-theoretic multiverse
- Category Latest Changes
- Started by Mike Shulman
- Comments 2
- Last comment by Urs
- Last Active 7 days ago

- Discussion Type
- discussion topicG2
- Category Latest Changes
- Started by Urs
- Comments 11
- Last comment by Urs
- Last Active Apr 14th 2019

added to

*G2*the definition of $G_2$ as the subgroup of $GL(7)$ that preserves the associative 3-form.

- Discussion Type
- discussion topicquaternion-Kähler manifold
- Category Latest Changes
- Started by Urs
- Comments 11
- Last comment by Urs
- Last Active Apr 13th 2019

- Discussion Type
- discussion topicM-theory on 8-manifolds
- Category Latest Changes
- Started by Urs
- Comments 4
- Last comment by Urs
- Last Active Apr 13th 2019

- Discussion Type
- discussion topicWolf space
- Category Latest Changes
- Started by Urs
- Comments 1
- Last comment by Urs
- Last Active Apr 13th 2019

- Discussion Type
- discussion topicquaternionic projective space
- Category Latest Changes
- Started by Urs
- Comments 1
- Last comment by Urs
- Last Active Apr 13th 2019

starting some minimum, cross-linking with

*quaternion-Kähler manifold*and*Sp(n).Sp(1)*

- Discussion Type
- discussion topicG2/SU(3) is the 6-sphere
- Category Latest Changes
- Started by Urs
- Comments 1
- Last comment by Urs
- Last Active Apr 13th 2019

- Discussion Type
- discussion topicSp(n).Sp(1)
- Category Latest Changes
- Started by Urs
- Comments 30
- Last comment by Urs
- Last Active Apr 13th 2019

am giving this group its own entry, so that every entry using it (such as quaternion-Kähler manifold) makes sure that the notation is not being confused with the direct product group.

What’s the source of this notation?

- Discussion Type
- discussion topiccentral product of groups
- Category Latest Changes
- Started by Urs
- Comments 2
- Last comment by Urs
- Last Active Apr 13th 2019

some minimum, for cross-linking with Sp(n).Sp(1)

- Discussion Type
- discussion topiclimit
- Category Latest Changes
- Started by Urs
- Comments 3
- Last comment by Alec Rhea
- Last Active Apr 12th 2019

I toiuched the formatting and the hyperlinking of the paragraphs on compatibility of limits with other universal constructions.

Merged the previous tiny subsections on this to a single one, now

*Compatibility with universal constructions*.added the hyperlink to the stand-alone entry

*adjoints preserve (co-)limits*.Will create an analogous stand-alone entry for

*limits commute with limits*.

- Discussion Type
- discussion topicFréchet space
- Category Latest Changes
- Started by Urs
- Comments 4
- Last comment by nLab edit announcer
- Last Active Apr 12th 2019

At

*Fréchet space*I have added to the Idea-section a paragraph motivating the definition via families of seminorms from the example of $\mathbb{R}^\infty = \underset{\longleftarrow}{\lim}_n \mathbb{R}^n$. And I touched the description of this example in the main text, now here.

- Discussion Type
- discussion topicYoneda embedding
- Category Latest Changes
- Started by Urs
- Comments 19
- Last comment by Urs
- Last Active Apr 12th 2019

Added Eric’s illustrations to the Idea-section at Yoneda embedding.

- Discussion Type
- discussion topicFréchet manifold
- Category Latest Changes
- Started by nLab edit announcer
- Comments 3
- Last comment by nLab edit announcer
- Last Active Apr 12th 2019

- Discussion Type
- discussion topicPaolo Piccinni
- Category Latest Changes
- Started by Urs
- Comments 4
- Last comment by zskoda
- Last Active Apr 12th 2019

- Discussion Type
- discussion topichyper-Kähler manifold > history
- Category Latest Changes
- Started by Urs
- Comments 1
- Last comment by Urs
- Last Active Apr 12th 2019

cleared this duplicate entry, merging it (and all its redirects) into

*hyperkähler manifold*

- Discussion Type
- discussion topichyperkähler manifold
- Category Latest Changes
- Started by Urs
- Comments 2
- Last comment by nLab edit announcer
- Last Active Apr 12th 2019

- Discussion Type
- discussion topicfinite rotation group
- Category Latest Changes
- Started by Urs
- Comments 39
- Last comment by Urs
- Last Active Apr 11th 2019

I am splitting off an entry

*classification of finite rotation groups*from*ADE classification*in order to collect statements and references specific to the classification of finite subgroups of $SO(3)$ and $SU(2)$.Is there a canonical reference for the proof of the classification statement? I find lots of lecture notes that give the proof, but all of them without citing sources or original publications of proofs.

- Discussion Type
- discussion topicMaxence Mayrand
- Category Latest Changes
- Started by nLab edit announcer
- Comments 2
- Last comment by David_Corfield
- Last Active Apr 11th 2019

- Discussion Type
- discussion topicspherical T-duality
- Category Latest Changes
- Started by Urs
- Comments 11
- Last comment by Urs
- Last Active Apr 11th 2019

created a quick pointer to, with a brief remark on,

*spherical T-duality*

- Discussion Type
- discussion topicCW-complex
- Category Latest Changes
- Started by Urs
- Comments 27
- Last comment by Urs
- Last Active Apr 11th 2019

added in CW-complex in the Examples section something about noncompact smooth manifolds.

Eventually it would be good to state here precisely Milnor’s theorem etc. Googling around I seem to see a lot of misleading imprecision in the usual statements along these lines (on Wikipedia and MO) concerning the distinctions between countably generated and general CW-complexes and concerning homotopy equivalence vs weak homotopy equivalence.

- Discussion Type
- discussion topicchoice sequence
- Category Latest Changes
- Started by Mike Shulman
- Comments 1
- Last comment by Mike Shulman
- Last Active Apr 10th 2019

- Discussion Type
- discussion topicaxiom of materialization
- Category Latest Changes
- Started by Mike Shulman
- Comments 2
- Last comment by Mike Shulman
- Last Active Apr 10th 2019

- Discussion Type
- discussion topicSO(8)
- Category Latest Changes
- Started by Urs
- Comments 10
- Last comment by Urs
- Last Active Apr 10th 2019

- Discussion Type
- discussion topicJoel David Hamkins
- Category Latest Changes
- Started by Mike Shulman
- Comments 1
- Last comment by Mike Shulman
- Last Active Apr 10th 2019

- Discussion Type
- discussion topiccontinuum hypothesis
- Category Latest Changes
- Started by Urs
- Comments 2
- Last comment by Mike Shulman
- Last Active Apr 10th 2019

- Discussion Type
- discussion topicSO(5)
- Category Latest Changes
- Started by Urs
- Comments 1
- Last comment by Urs
- Last Active Apr 10th 2019

- Discussion Type
- discussion topicMessier 87
- Category Latest Changes
- Started by Urs
- Comments 1
- Last comment by Urs
- Last Active Apr 10th 2019

- Discussion Type
- discussion topicMilky Way
- Category Latest Changes
- Started by Urs
- Comments 1
- Last comment by Urs
- Last Active Apr 10th 2019

- Discussion Type
- discussion topicEvent Horizon Telescope
- Category Latest Changes
- Started by Urs
- Comments 2
- Last comment by Urs
- Last Active Apr 10th 2019

brief entry to go with the list of

*experiments*, and to record today’s- Event Horizon Telescope Collaboration,
*First M87 Event Horizon Telescope Results. I. The Shadow of the Supermassive Black Hole*, The Astrophysical Journal Letters, Volume 875, Number 1, 2019 (doi:10.3847/2041-8213/ab0ec7)

- Event Horizon Telescope Collaboration,