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- Discussion Type
- discussion topicalgebras as coslice objects
- Category Latest Changes
- Started by HewWolff
- Comments 5
- Last comment by Urs
- Last Active Sep 13th 2014

I have not yet made this change – as a newbie, I want to get an opinion first.

associative unital algebra describes an $R$-algebra $A$, for $R$ commutative, as a “ring under $R$”. From under category, this is just an object in the coslice category $R \downarrow \operatorname{Ring}$: a map $R \to A$, where $A$ is another ring. However, I believe that such a map gives an $R$-algebra only if its image is in the

*center*of $A$ (for example, Wikipedia). I’m not sure how to fix that. Maybe we should just remove the “under $R$” item from that first page. Thoughts?

- Discussion Type
- discussion topicgauge theory from AdS-CFT -- table
- Category Latest Changes
- Started by Urs
- Comments 32
- Last comment by Urs
- Last Active Sep 12th 2014

since the story of the various duals, compactifications and twists of gauge field theories which constitute “Witten’s grand story” (or whatever it should be called in total) gets a bit long, I thought it would be good to have a birds-eye view digest of it – and so I created a survey table

*gauge theory from AdS-CFT – table*and included it into some relevant entries.

(There is clearly still room for expansion and further details, but maybe it’s a start).

- Discussion Type
- discussion topicDirichlet theta function
- Category Latest Changes
- Started by Urs
- Comments 1
- Last comment by Urs
- Last Active Sep 10th 2014

finally created a minimum at

*Dirichlet theta function*, cross-linked with*Dirichlet character*and*Dirichlet L-function*and added it to the table (bottom left entry)(I have gotten a funny problem with my Opera browser having trouble loading nLab pages. Something makes it choke. For instance when I try to edit a page it tends to show me a blank screen, but when I then go to edit the same page with another browser, then that informs me that the page is locked, so Opera did get to that point, but then got stuck. This happens since the last few days. I tried clearing caches, but it didn’t seem to help. Hm. )

- Discussion Type
- discussion topicwww.fuw.edu.pl/~slworono/PDF-y/OP.pdf
- Category Latest Changes
- Started by Tim_Porter
- Comments 2
- Last comment by Urs
- Last Active Sep 10th 2014

Someone set up a new page with title www.fuw.edu.pl/~slworono/PDF-y/OP.pdf. It seems that this is an attempt by Stanisław Lech Woronowicz to create a nlab entry. Should we just convert it to a usual format page for him? The pdf file is a copy of his paper:Operator theory in the $C^*$-algebra framework., joint with K.Napi ́orkowski.

- Discussion Type
- discussion topicSpin Chern-Simons theory
- Category Latest Changes
- Started by Urs
- Comments 1
- Last comment by Urs
- Last Active Sep 9th 2014

started some bare minimum at

*Spin Chern-Simons theory*

- Discussion Type
- discussion topicmoduli space of framed manifolds
- Category Latest Changes
- Started by Urs
- Comments 1
- Last comment by Urs
- Last Active Sep 9th 2014

had added some minimum at

*moduli space of framed manifolds*.Are there any general results characterizing moduli of $(d+1)$-framings on $d$-manifolds?

- Discussion Type
- discussion topicholomorphic line 2-bundle
- Category Latest Changes
- Started by Urs
- Comments 26
- Last comment by Urs
- Last Active Sep 6th 2014

brief entry

*holomorphic line 2-bundle*, just to have the link and to record the reference there

- Discussion Type
- discussion topicBeilinson regulator
- Category Latest Changes
- Started by Urs
- Comments 3
- Last comment by Urs
- Last Active Sep 4th 2014

added at

*Beilinson regulator*a section*Geometric constructions*such as to finally give a canonical home to the pointer to Brylinki’s article that David Roberts keeps highlighting (in other threads).

- Discussion Type
- discussion topicFriedlander-Milnor isomorphism conjecture
- Category Latest Changes
- Started by Urs
- Comments 1
- Last comment by Urs
- Last Active Sep 3rd 2014

started something at

*Friedlander-Milnor isomorphism conjecture*. But handle with care, I am only just watching the video linked to there.

- Discussion Type
- discussion topicWaldhausen K-theory of a dg-category
- Category Latest Changes
- Started by adeelkh
- Comments 3
- Last comment by adeelkh
- Last Active Sep 3rd 2014

Added a stub at Waldhausen K-theory of a dg-category. I call this the

*Waldhausen*K-theory and not simply K-theory because I imagine that there should also be a more intrinsic definition not passing through Waldhausen categories or stable infinity-categories.

- Discussion Type
- discussion topicclassical anomaly
- Category Latest Changes
- Started by Urs
- Comments 3
- Last comment by Urs
- Last Active Sep 3rd 2014

created

*classical anomaly*

- Discussion Type
- discussion topicvacuum amplitude
- Category Latest Changes
- Started by Urs
- Comments 6
- Last comment by Urs
- Last Active Sep 2nd 2014

started some minimum at

*vacuum amplitude*. Briefly mentioned relation to a) generating functionals for correlators and b) to zeta functions and c) to expected evanishing in supersymmetric theoriesRemarked that in view of b) and c) one is tempted to expect some relation between 1-loop vacuum amplitudes of supersymmetric field/string theories with the Riemann hypothesis. Added a pointer to the article ACER 11 which seems to find just that.

If anyone has further pointers to literature relating vanishing of susy 1-loop vacuum amplitudes and (generalized) Riemann hypotheses, please drop me a note.

- Discussion Type
- discussion topiczeta-, eta-, theta-, L-functions -- table
- Category Latest Changes
- Started by Urs
- Comments 14
- Last comment by David_Corfield
- Last Active Sep 2nd 2014

created a table-for-inclusion and included it into the relevant entries:

*zeta-functions and eta-functions and theta-functions and L-functions – table*Presently it looks like this:

The main statement of this analogy is discussed for instance on the first pages of

- Ken Richardson,
*Introduction to the Eta-invariant*(pdf)

I have added some paragraphs at

*eta invariant*, accordingly.- Ken Richardson,

- Discussion Type
- discussion topicvacuum energy
- Category Latest Changes
- Started by Urs
- Comments 1
- Last comment by Urs
- Last Active Sep 2nd 2014

started some minimum at

*vacuum energy*, but running out of battery now.

- Discussion Type
- discussion topicMellin transform
- Category Latest Changes
- Started by Urs
- Comments 1
- Last comment by Urs
- Last Active Sep 2nd 2014

started some minimum at

*Mellin transform*

- Discussion Type
- discussion topicArtin L-functions analogous to zeta of flat-connection-twisted Laplace operator
- Category Latest Changes
- Started by Urs
- Comments 18
- Last comment by Urs
- Last Active Sep 1st 2014

This here to collect resources on the observation that – in view of pertinent arithmetic/differential-geometry analogies – an Artin L-function of a Galois representation looks like the zeta function of a Laplace operator of a Dirac operator twisted by a flat bundle.

I currently see this in the literature in three steps:

the Selberg zeta function, which is originally defined as some Euler product, is specifially equal to an Euler product of characteristic polynomials (just as the Artin L-function). This turns out to be due to Gangolli77 and Fried86, and I have collected these references now at

*Selberg zeta function – Analogy with Artin L-function*with a cross-linking paragraph also at*Artin L-function*itselfmore specifically, those characteristic polynomials are those of the monodromies/holonomies of the given group representation, regarded as a flat connection. This is prop. 6.3 in Bunke-Olbrich 94.

finally, that product over characteristic polynomials of monodromies is indeed the zeta function of the bundle-twisted Laplace operator. This is the main point in Bunke-Olbrich 94, somehow, but I still need to fiddle with extracting a more explicit version of this statement.

- Discussion Type
- discussion topicregular representation
- Category Latest Changes
- Started by Andrew Stacey
- Comments 11
- Last comment by zskoda
- Last Active Sep 1st 2014

I made a start on regular representation (via a stub from normalizer). My first thought was to made this a generic regular representation page so I put in definitions for groups and algebras.

Once I’d created the page I thought that it could be said to be an example of a more general thing whereby a monoid acts on itself. However, someone’s already editing the page (that was fast!) so I’ll have to wait to put that in.

(Unless the anonymous coward reads this and decides to put it in themselves!)

- Discussion Type
- discussion topiczeta function
- Category Latest Changes
- Started by zskoda
- Comments 12
- Last comment by Urs
- Last Active Sep 1st 2014

Updates to zeta function.

- Discussion Type
- discussion topiccharacteristic variety
- Category Latest Changes
- Started by zskoda
- Comments 3
- Last comment by Michael_Bachtold
- Last Active Aug 31st 2014

Some time ago I started a stub characteristic variety to record few references, mainly in D-module context. Regarding that the related notion of a characteristic ideal also appears in the treatment of Iwasawa polynomial and Alexander polynomial which Urs wants to understand from the point of view of connections and differential refinements of cohomology, maybe we should do some effort to make some pages which will connect various notions of characteristic ideals and their loci across various subjects. I just recorded

- Andrea Bandini, Francesc Bars, Ignazio Longhi,
*Characteristic ideals and Iwasawa theory*, arxiv/1310.0680;*Characteristic ideals and Selmer groups*, arxiv/1404.2788

at characteristic ideal for the version in the context of Iwasawa theory.

- Andrea Bandini, Francesc Bars, Ignazio Longhi,

- Discussion Type
- discussion topicLanglands correspondence
- Category Latest Changes
- Started by Urs
- Comments 7
- Last comment by Urs
- Last Active Aug 28th 2014

gave

*Langlands correspondence*an actual Idea-section.(Am in a rush and on a horrible wifi connection. Need to proof-read and add more links later.)

- Discussion Type
- discussion topicDedekind eta function
- Category Latest Changes
- Started by Urs
- Comments 1
- Last comment by Urs
- Last Active Aug 28th 2014

added the following story to the Properties-section of

*Dedekind eta function*and also to the Examples-section of*functional determinant*and*zeta function of an elliptic differential operator*:

For $E = \mathbb{C}/(\mathbb{Z}\oplus \tau \mathbb{Z})$ a complex torus (complex elliptic curve) equipped with its standard flat Riemannian metric, then the zeta function of the corresponding Laplace operator $\Delta$ is

$\zeta_{\Delta} = (2\pi)^{-2 s} E(s) \coloneqq (2\pi)^{-2 s} \underset{(k,l)\in \mathbb{Z}\times\mathbb{Z}-(0,0)}{\sum} \frac{1}{{\vert k +\tau l\vert}^{2s}} \,.$The corresponding functional determinant is

$\exp( E^\prime(0) ) = (Im \tau)^2 {\vert \eta(\tau)\vert}^4 \,,$where $\eta$ is the Dedekind eta function.

- Discussion Type
- discussion topicArtin L-function
- Category Latest Changes
- Started by Urs
- Comments 1
- Last comment by Urs
- Last Active Aug 28th 2014

Recorded the basic idea at

*Artin L-function*Also: added the following paragraph to the Idea-section at

*Langlands correspondence*(below the numbered two items stating the conjectured correspondence between Galois representations and automorphic representations):Moreover, to each such automorphic representation is associated an L-function – the

*automorphic L-function*– and in generalization of Artin reciprocity the conjecture is that the Artin L-function associated with the given Galois representation is equal to the automorphic L-function of the corresponding automorphic representation.

- Discussion Type
- discussion topicclass number formula
- Category Latest Changes
- Started by Urs
- Comments 12
- Last comment by DavidRoberts
- Last Active Aug 28th 2014

I have added the following sentence to

*class number formula*and to all the other entries that the sentence links to:

Given a number field $K$, the Dedekind zeta function $\zeta_K$ of $K$ has a simple pole at $s = 1$. The

$\underset{s\to 1}{\lim} (s-1) \zeta_K(s) \propto ClassNumber_K \cdot Regulator_K \,.$*class number formula*says that its residue there is proportional the product of the regulator with the class number of $K$

In particular I have also created

*regulator of a number field*and cross-linked it with*Beilinson regulator*, which I have renamed to*higher regulator*.

- Discussion Type
- discussion topiczeta function regularization
- Category Latest Changes
- Started by Urs
- Comments 2
- Last comment by Urs
- Last Active Aug 27th 2014

gave

*zeta function regularization*its own entry and expanded a bit, added more pertinent references

- Discussion Type
- discussion topictorsion module
- Category Latest Changes
- Started by Urs
- Comments 1
- Last comment by Urs
- Last Active Aug 26th 2014

just to clean up entries, I have given

*torsion module*its own entry (the keyword used to have non-overlapping discussion at*torsion subgroup*and at*torsion approximation*)

- Discussion Type
- discussion topiczeta function of an elliptic differential operator
- Category Latest Changes
- Started by Urs
- Comments 2
- Last comment by Urs
- Last Active Aug 25th 2014

added to

*zeta function of an elliptic differential operator*also some first minimum comments on the functional determinant and zeta-function regularization

- Discussion Type
- discussion topicidele class group
- Category Latest Changes
- Started by Urs
- Comments 5
- Last comment by Urs
- Last Active Aug 25th 2014

added the definition of

*idele class group*to*group of ideles*, with a brief pointer to its role in the moduli stack of line bundles. Added both then to the*function field analogy – table*

- Discussion Type
- discussion topicEuler product
- Category Latest Changes
- Started by Urs
- Comments 2
- Last comment by zskoda
- Last Active Aug 25th 2014

started a minimum at

*Euler product*, the main point being for the moment to mention briefly how Euler product forms naturally appears from the point of view of adelic integration/Iwasawa-Tate theory.

- Discussion Type
- discussion topicstable dg-category
- Category Latest Changes
- Started by adeelkh
- Comments 9
- Last comment by zskoda
- Last Active Aug 25th 2014

I have renamed the entry pretriangulated dg-category to stable dg-category. I think this is a logical move that emphasizes the close relationship with the notions of stable (infinity,1)-category and stable model category. If anyone disagrees I would be interested to hear why. I have also edited the body of the page to give an exposition more in line with modern references like Cisinski-Tabuada. However I have adopted the term dg-presheaf for what is usually called (right) dg-module. This seems much more natural to me, but again I am open to hearing any arguments against it. When I get a minute I will also update the entry dg-category to match the conventions of this page.

Also, I never liked the term “quasi-equivalence”. I think that this should just be called equivalence of dg-categories, or maybe Dwyer-Kan equivalence if this is too ambiguous. Any thoughts?

- Discussion Type
- discussion topicBeilinson monad
- Category Latest Changes
- Started by barakat
- Comments 5
- Last comment by barakat
- Last Active Aug 25th 2014

@Urs: I do not quite agree with the sentence “This is unrelated to other notions of monads” in Beilinson monad.

One can indeed view the Beilinson monad as the monad of an adjoint equivalence between $\mathfrak{Coh} \mathbb{P}^n$ (interpreted as the heart of $D^b \mathbb{P}^n$ and some category of linear complexes over an exterior algebra (the Koszul dual of the Cox ring of $\mathbb{P}^n$).

- Discussion Type
- discussion topicadelic integration
- Category Latest Changes
- Started by Urs
- Comments 2
- Last comment by Urs
- Last Active Aug 23rd 2014

created a minimum at

*adelic integration*, for the moment this is just a glorified pointer to Fesenko 08, section 3

- Discussion Type
- discussion topicdifferential cohesion and quasicoherent sheaves
- Category Latest Changes
- Started by Urs
- Comments 6
- Last comment by Urs
- Last Active Aug 22nd 2014

At

*differential cohesion*there used to be the statement that every object $X$ canonically has a “spectrum” given by $(Sh_{\mathbf{H}}(X), \mathcal{O}_X)$, but the (simple) argument that $\mathcal{O}_X$ indeed satisfies the axioms of a structure sheaf used to be missing. I have now added it here.

- Discussion Type
- discussion topicrng
- Category Latest Changes
- Started by Urs
- Comments 10
- Last comment by TobyBartels
- Last Active Aug 22nd 2014

added references.

Any book that develops a bit of algebraic geometry of non-unital commutative rings or one that discusses what would be hte major things that break?

- Discussion Type
- discussion topicstatistic, statistics, parastatistics
- Category Latest Changes
- Started by zskoda
- Comments 3
- Last comment by TobyBartels
- Last Active Aug 22nd 2014

- Discussion Type
- discussion topicnonunital Ek-algebra
- Category Latest Changes
- Started by Urs
- Comments 1
- Last comment by Urs
- Last Active Aug 22nd 2014

started a wee bit at

*nonunital Ek-algebra*

- Discussion Type
- discussion topicaugmented A-infinity algebra
- Category Latest Changes
- Started by Urs
- Comments 13
- Last comment by Urs
- Last Active Aug 22nd 2014

started

*augmented A-infinity algebra*

- Discussion Type
- discussion topicreflective subcategory
- Category Latest Changes
- Started by barakat
- Comments 4
- Last comment by zskoda
- Last Active Aug 21st 2014

- Corrected the associated monad in reflective subcategory:

---

The monad (Q^* Q_*,Q^*\varepsilon Q_*,\eta) associated with the adjunction

->

The monad (Q_* Q_^*,\varepsilon,Q_* \eta Q_^*) associated with the adjunction

---

- Discussion Type
- discussion topicinfinity-field
- Category Latest Changes
- Started by David_Corfield
- Comments 3
- Last comment by Urs
- Last Active Aug 21st 2014

I added a clarifying clause to infinity-field so it now reads

The Morava K-theory A-∞ rings $K(n)$ are essentially the only $A_\infty$-fields. See at

*Morava K-theory – As infinity-Fields*, where $K(0) \simeq H \mathbb{Q}$ and we define $K(\infty)$ as $H \mathbb{F}_p$.This is from Lurie’s lectures. What precisely does he mean? He says in lecture 24 that for $k$ any field that its E-M spectrum $H k$ is an infinity-field, so the “essentially” is doing some work. Is the idea that all infinity-fields are $K(n)$-modules (cor 10, lecture 25), so the $K(n)$ essentially cover things?

On another point, would there be a higher form of the rational/p-adic fracturing of $\mathbb{Z}$, involving the $K(n)$?

- Discussion Type
- discussion topicArakelov geometry
- Category Latest Changes
- Started by Urs
- Comments 2
- Last comment by Urs
- Last Active Aug 19th 2014

collected some introductions and surveys

- Discussion Type
- discussion topiccompletion of a module
- Category Latest Changes
- Started by Urs
- Comments 4
- Last comment by Urs
- Last Active Aug 19th 2014

started

*completion of a module*, for the moment mainly so as to record a bunch of basic definitions and facts about completion of $\infty$-modules from DAG12

- Discussion Type
- discussion topiccanonical transformation (Hamiltonian mechanics)
- Category Latest Changes
- Started by Urs
- Comments 5
- Last comment by Urs
- Last Active Aug 18th 2014

I have given the notion of

*canonical transformation*as used in Hamiltonian mechanics its own brief page.So in particular I removed the redirect of that term to

*canonical morphism*and instead added disambiguation lines on the top of both entries. I think this is justified: the term “canonical transformation” has been standard since ancient times in Hamiltonian mechanics and is in each and every textbook on the matter. On the other hand the same term as referring to canonical morphisms was mainly the proposal of one single person in category theory, and never caught up much, I think. (Also I find the term ill-motivated in category theory in the first place).Therefore, while the disambiguation redirects ensure that both notions still can be found, I think it is clear that the default meaning must be that in Hamiltonian mechanics.

- Discussion Type
- discussion topicarithmetic cohesion -- table
- Category Latest Changes
- Started by Urs
- Comments 1
- Last comment by Urs
- Last Active Aug 15th 2014

started a table-for-inclusion

*arithmetic cohesion – table*and included it into relevant entries.In the course of this I started a minimum at

*adic residual*.

- Discussion Type
- discussion topichigher local field
- Category Latest Changes
- Started by Urs
- Comments 2
- Last comment by DavidRoberts
- Last Active Aug 15th 2014

created a minimum at

*higher local field*and*higher arithmetic geometry*and added disambiguation with “E-∞ arithmetic geometry”.

- Discussion Type
- discussion topicsynthetic differential infinity-groupoid
- Category Latest Changes
- Started by Urs
- Comments 16
- Last comment by Urs
- Last Active Aug 14th 2014

I have worked on the entry synthetic differential infinity-groupoid;

added a brief remark in the Idea section;

spelled out statement and proof that $SynthDiff \infty Grpd$ is totally $\infty$-connected over $Smooth \infty Grpd$;

began some discussion on how the induced relative fundamental $\infty$-groupoid functor is $\mathbf{\Pi}_{inf}$: the infinitesimal path $\infty$-groupoid functor, such that $\mathbf{\Pi}_{inf}(X)$ is the de Rham space of $X$ and a morphism $\mathbf{\Pi}_{inf}(X) \to \infty Mod$ an $\infty$-stack of D-modules on $X$. But this deserves more discussion.

Concerning the writeup of the second point I had myself confused about the direction of one of the arrows for a while. Hope I got it right now.

- Discussion Type
- discussion topichausdorff locally convex space
- Category Latest Changes
- Started by Tim_Porter
- Comments 3
- Last comment by TobyBartels
- Last Active Aug 13th 2014

Look at hausdorff locally convex space.

- Discussion Type
- discussion topictorsion approximation
- Category Latest Changes
- Started by Urs
- Comments 1
- Last comment by Urs
- Last Active Aug 12th 2014

created an entry for

*torsion approximation*, mainly to be able to refer to this concept by a link.

- Discussion Type
- discussion topicmanifolds via idempotent splitting
- Category Latest Changes
- Started by Thomas Holder
- Comments 9
- Last comment by Thomas Holder
- Last Active Aug 10th 2014

Unfortunately, I am lacking chocolat medals (as well as the authority to award them), but thanks to the author (presumably Todd) who graced Karoubi envelope with the proof that smooth manifolds result from open sets by idempotent splitting.

I have added a reference to Lawvere’s Perugia notes where this appeared as an exercise.

Entre parenthèses: it appears to me that it’d be better to have the proof at the page for smooth manifolds and to mention the result only at Karoubi envelope as I think this is kind of a butterfly at Karoubi though a beautiful one but an important result for manifolds.

- Discussion Type
- discussion topicPicard-Lefschetz theory
- Category Latest Changes
- Started by zskoda
- Comments 2
- Last comment by Urs
- Last Active Aug 10th 2014

- Some rough outline at Picard-Lefschetz theory.

- Discussion Type
- discussion topicgroupoid object in an (oo,1)-category
- Category Latest Changes
- Started by Urs
- Comments 14
- Last comment by Urs
- Last Active Aug 10th 2014

polished and expanded somewhat the entry groupoid object in an (infinity,1)-category

- Discussion Type
- discussion topicFermat quotient
- Category Latest Changes
- Started by Urs
- Comments 1
- Last comment by Urs
- Last Active Aug 10th 2014

created a bare minimum at

*Fermat quotient*.

- Discussion Type
- discussion topicNew inclusion table: generalized uniform structures
- Category Latest Changes
- Started by TobyBartels
- Comments 3
- Last comment by TobyBartels
- Last Active Aug 9th 2014

I created generalized uniform structures - table in the style of all of those tables that Urs makes and included it on most of the relevant pages. (I left the pages on the simplest concepts, the binary relations.)

I hope that the headers “monad on an object” and “monad on a pro-object” are accurate. These should be objects in an equipment, I think. Perhaps Mike can help me figure out what equipments are relevant here.

- Discussion Type
- discussion topicPrometric spaces
- Category Latest Changes
- Started by TobyBartels
- Comments 1
- Last comment by TobyBartels
- Last Active Aug 9th 2014

I have greatly expanded the basic definition at prometric space to show other ways to look at the concept.

- Discussion Type
- discussion topicadjoint lifting theorem
- Category Latest Changes
- Started by Yaron
- Comments 10
- Last comment by DavidRoberts
- Last Active Aug 8th 2014

Started adjoint lifting theorem. For now, it only includes a version for lifting

*left*adjoints (I still haven’t read Johnstone’s 1975 paper for the case of right adjoints). I hope there is no substantial error in the appliaction for cocompleteness.

- Discussion Type
- discussion topicRicatti differential equation
- Category Latest Changes
- Started by zskoda
- Comments 1
- Last comment by zskoda
- Last Active Aug 5th 2014

- Discussion Type
- discussion topicmovable singularity
- Category Latest Changes
- Started by zskoda
- Comments 1
- Last comment by zskoda
- Last Active Aug 5th 2014

New entry movable singularity (for ODE’s with complex time) redirecting also fixed singularity.

- Discussion Type
- discussion topicTannaka duality for geometric stacks
- Category Latest Changes
- Started by Urs
- Comments 7
- Last comment by David_Corfield
- Last Active Aug 4th 2014

started stub on Tannaka duality for geometric stacks, but need to interrupt now.

The theorem there can be read as justifying the point of view of derived noncommutative geometry to regard the 2-algebra $QC(X)$ as a valid replacement for the 1-algebra $\mathcal{O}(X)$.

- Discussion Type
- discussion topicgroup scheme, scheme
- Category Latest Changes
- Started by Stephan A Spahn
- Comments 10
- Last comment by David_Corfield
- Last Active Aug 1st 2014

I edited group scheme and scheme a bit.

- Discussion Type
- discussion topicJónsson-Tarski, Thompson& Higman, and self-similarity
- Category Latest Changes
- Started by Thomas Holder
- Comments 3
- Last comment by Thomas Holder
- Last Active Jul 31st 2014

Fumbling around Jonsson-Tarski topos I’ve created entries on Thompson group and Higman’s theorem. Basically some links to further material. As Jónsson-Tarski seems to bring together a lot of stuff from different fields, I think we should have also some material on Tom’s work on self-similarity here.

- Discussion Type
- discussion topicordinal subdivision
- Category Latest Changes
- Started by Tim_Porter
- Comments 4
- Last comment by Todd_Trimble
- Last Active Jul 30th 2014

I created ordinal subdivision to get rid of a grey link in subdivision, but it just gives a reference to the paper by Phil Ehlers and myself. I need to check at ordinal sum to see what was put there before continuing.

- Discussion Type
- discussion topicETCC/ET2CC
- Category Latest Changes
- Started by Thomas Holder
- Comments 10
- Last comment by Thomas Holder
- Last Active Jul 29th 2014

I have expanded on ETCC and introduced a section on ET2CC which I could occasionally fill with Mike’s ideas from MO in case all n-categorists are lying on the beach. I would also propose to replace the current ’idea’ section with what is right now called ’overview’ or some reworking of that.

I think it best to keep everything in a single entry given that these ideas on ETCC with or without 2 meet only a limited enthusiasm in the HOTT times.