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- Discussion Type
- discussion topiccoherent cohomology
- Category Latest Changes
- Started by Urs
- Comments 17
- Last comment by Zhen Lin
- Last Active Jun 3rd 2014

we didn’t have any entry defining

*coherent cohomology*, did we?(I notice that we are lacking also an entry

*coherent object*. That really needs to be created.)

- Discussion Type
- discussion topicmorphism of finite type
- Category Latest Changes
- Started by Urs
- Comments 3
- Last comment by zskoda
- Last Active Jun 3rd 2014

quick stub for morphism of finite type (redirecting also morphism of locally finite type)

- Discussion Type
- discussion topicLinguistics
- Category Latest Changes
- Started by Colin Zwanziger
- Comments 2
- Last comment by Todd_Trimble
- Last Active Jun 2nd 2014

Added some new material to linguistics.

- Discussion Type
- discussion topiccharacteristic element of a bilinear form
- Category Latest Changes
- Started by Urs
- Comments 1
- Last comment by Urs
- Last Active Jun 2nd 2014

- Discussion Type
- discussion topicintersection theory
- Category Latest Changes
- Started by Urs
- Comments 1
- Last comment by Urs
- Last Active May 31st 2014

gave

*intersection theory*an Idea section. Clearly, there is room for improvement, but it’s a start.In the course of this I have created at stub for

*Bézout’s theorem*, gave*Serre intersection formula*an Idea-section (please feel invited to expand further!) and cross-linked all this and a few more entries.

- Discussion Type
- discussion topicdivisor (geometry)
- Category Latest Changes
- Started by Urs
- Comments 1
- Last comment by Urs
- Last Active May 31st 2014

added some minimum of content to the old stub

*divisor (algebraic geometry)*

- Discussion Type
- discussion topicpolarized algebraic variety
- Category Latest Changes
- Started by Urs
- Comments 2
- Last comment by Urs
- Last Active May 31st 2014

started

*polarized algebraic variety*

- Discussion Type
- discussion topicfirst Chern class
- Category Latest Changes
- Started by Urs
- Comments 2
- Last comment by Urs
- Last Active May 31st 2014

added the definition

*in complex analytic geometry*with a pointer to*degree of a coherent sheaf*

- Discussion Type
- discussion topicexponential exact sequence
- Category Latest Changes
- Started by Urs
- Comments 2
- Last comment by Urs
- Last Active May 31st 2014

created

*exponential exact sequence*with the obvious basic comments. Cross-linked with*Planck’s constant*, with*multiplicative group*and*circle group*, and with*Kummer sequence*.

- Discussion Type
- discussion topicTheta characteristic
- Category Latest Changes
- Started by Urs
- Comments 1
- Last comment by Urs
- Last Active May 31st 2014

added to

*Theta characteristic*two further brief Properies-paragarphs:*As metaplectic and Spin-structure over (Kähler-)polarized varieties*and*Over intermediate Jacobians*.

- Discussion Type
- discussion topicequivariant and Bredon cohomology
- Category Latest Changes
- Started by Urs
- Comments 30
- Last comment by Mike Shulman
- Last Active May 30th 2014

I created at equivariant cohomology separate subsections for, so far, Borel equivariant and Bredon equivariant cohomology.

At Bredon cohomology I added a sentence about the coefficient objects.

- Discussion Type
- discussion topicninebrane structure
- Category Latest Changes
- Started by Urs
- Comments 3
- Last comment by Urs
- Last Active May 30th 2014

Since Hisham’s article came out

- Hisham Sati,
*Ninebrane structures*(arXiv:1405.7686)

I briefly created a stub entry

*ninebrane structure*and expanded the*higher spin structure - table*accordingly. More should be done here, but I don’t have the leisure right now.- Hisham Sati,

- Discussion Type
- discussion topicQuillen Q-construction
- Category Latest Changes
- Started by Urs
- Comments 1
- Last comment by Urs
- Last Active May 29th 2014

started a minimum at

*Quillen Q-construction*

- Discussion Type
- discussion topicSpectral Schemes
- Category Latest Changes
- Started by Urs
- Comments 5
- Last comment by Urs
- Last Active May 28th 2014

The nLab entry Spectral Schemes has existed for a long time, now finally the article with that title exists, too. ;-) See the link there

- Discussion Type
- discussion topicmoduli space of bundles
- Category Latest Changes
- Started by Urs
- Comments 1
- Last comment by Urs
- Last Active May 28th 2014

only now realized that Zoran had an old entry

*moduli space of bundles*. Have now vigorously cross-linked it with a bunch of related entries

- Discussion Type
- discussion topicroot of unity
- Category Latest Changes
- Started by Urs
- Comments 4
- Last comment by Todd_Trimble
- Last Active May 26th 2014

I gave

*root of unity*its own entry (it used to redirect to*root*), copied over the paragraph on properties of roots of unities in fields, and added a paragraph on the arithmetic geometry description via $\mu_n = Spec(\mathbb{Z}[t](t^n-1))$ and across-pointer with*Kummer sequence*.

- Discussion Type
- discussion topicKummer-Artin-Schreier-Witt exact sequence
- Category Latest Changes
- Started by Urs
- Comments 1
- Last comment by Urs
- Last Active May 26th 2014

created

*Kummer-Artin-Schreier-Witt exact sequence*, but except for some references, there is no actual content yet

- Discussion Type
- discussion topicanti-modal type
- Category Latest Changes
- Started by Urs
- Comments 1
- Last comment by Urs
- Last Active May 26th 2014

created a brief entry

*anti-modal type*, since I wanted to be able to point to this. Cross-linked with localizing subcategory etc.

- Discussion Type
- discussion topicRepresentability theorems
- Category Latest Changes
- Started by Urs
- Comments 5
- Last comment by Urs
- Last Active May 26th 2014

created some stub entries for keywords at

*Representability theorems*and cross-linked a bit.

no content yet besides a minimal Idea-sentence, for the moment just so as to get some pointers into place

- Discussion Type
- discussion topicspectrum of an abelian category
- Category Latest Changes
- Started by zskoda
- Comments 10
- Last comment by Urs
- Last Active May 25th 2014

Several related new entries: Gabriel-Rosenberg theorem, spectrum of an abelian category, local abelian category.

- Discussion Type
- discussion topicarc-connected space
- Category Latest Changes
- Started by Todd_Trimble
- Comments 2
- Last comment by TobyBartels
- Last Active May 25th 2014

I added some material on arc-connected spaces to connected space.

I added also a reference to Willard’s General Topology, together with this online link to a Scribd document: Willard. Is this kosher (I am guessing this document is not “pirated”, but I’m not sure)?

- Discussion Type
- discussion topicLie infinity-algebroid representatio
- Category Latest Changes
- Started by Urs
- Comments 1
- Last comment by Urs
- Last Active May 23rd 2014

Prompted by a question which I received, I went and tried to streamline the old entry

*Lie infinity-algebroid representation*a little:moved the pevious “Properties”-discussion of complexes of holomorphic bundles to the Examples-section;

added the example of $L_\infty$-algebra extensions

added more information to the References-section

cross-linked a bit more with infinity-action and with L-infinity algebra cohomology etc.

- Discussion Type
- discussion topicPicard infinity-stack
- Category Latest Changes
- Started by Urs
- Comments 5
- Last comment by Urs
- Last Active May 22nd 2014

I started a separate page for

*Picard stack*(which used to be just a redirect to*Picard scheme*), stated the general nonsense idea with a pointer to Lurie’s thesis, where this essentially appears.(BWT, where in the DAG series did this end up? I forget.)

Of course the upshot is that it’s simply the internal hom/mapping stack $\mathbf{Pic}(X) = [X,\mathbf{B}\mathbb{G}_m]$. I have a question here: it seems clear that the higher versions $[X, \mathbf{B}^k \mathbb{G}_m]$ want to be called the higher intermediate Jacobians (their deformation theory at 0 are the Artin-Mazur formal groups). Why does nobody say this? (Or if they do, where?)

- Discussion Type
- discussion topicGAGA
- Category Latest Changes
- Started by Kevin Lin
- Comments 5
- Last comment by zskoda
- Last Active May 22nd 2014

- Added stub for GAGA.

- Discussion Type
- discussion topicBrauer infinity-stack
- Category Latest Changes
- Started by Urs
- Comments 7
- Last comment by Urs
- Last Active May 22nd 2014

Over in the

*thread on “Picard infinity-stack”*we turned to discussion of*Brauer stack*. Just for completeness I should probably make this a separate thread here: I had created*Brauer stack*for the moment only with the following Idea-section

It is traditional to speak, for a suitable scheme $X$, of its

$\mathbf{Br}(X) \coloneqq [X,\mathbf{B}^2 \mathbb{G}_m]$*Picard group*and of its*Brauer group*. Moreover, it is a classical fact that under suitable conditions the former admits itself a canonical geometric structure that makes it the*Picard scheme*of $X$. Still well known, if maybe less commonly highlighted, is that this is just the 0-truncation of the Picard stack of $X$, which is simply the mapping stack $[X, \mathbf{B}\mathbb{G}_m]$ into the delooping of the multiplicative group. In this form this applies immediately also to more general context such as E-∞ geometry ("spectral geometry") and gives a concept of*Picard ∞-stack*("derived Picard stack"). Given this and the relation of the Brauer group to étale cohomology it is clear that the Brauer group similarly arises as the torsion subgroup of the 0-truncation of the ∞-stack which*ought*to be called the**Brauer stack**, given as the mapping stackinto the second delooping of the multiplicative group (modulating line 2-bundles). Indeed, just as the Picard stack turns under Lie integration (evaluation on infinitesimally thickened points) and 0-truncation into what is commonly called the

*formal Picard group*, so this Brauer $\infty$-stack similarly gives what is commonly called the*formal Brauer group*.However, while therefore the terminology "Brauer stack" is the evident continuation of a traditional pattern (which in the other direction continues with the group of units and the mapping scheme $[X,\mathbb{G}_,]$), it seems that this terminology has never been introduced in the literature (at time of this writing). (?)

- Discussion Type
- discussion topicholomorphic vector bundle
- Category Latest Changes
- Started by Urs
- Comments 3
- Last comment by Urs
- Last Active May 21st 2014

at

*holomorphic vector bundle*I have started a section titled*As complex vector bundles with holomorphically flat connections*.This deserves much more discussion (and maybe in a dedicated entry), but for the moment I have there the following paragraphs (with lots of room for further improvement):

+– {: .num_theorem #KoszulMalgrangeTheorem}

###### Theorem

Holomorphic vector bundles over a complex manifold are equivalently complex vector bundles which are equipped with a holomorphic flat connection. Under this identification the Dolbeault operator $\bar \partial$ acting on the sections of the holomorphic vector bundle is identified with the holomorphic component of the covariant derivative of the given connection.

The analogous statement is true for generalization of vector bundles to chain complexes of module sheaves with coherent cohomology.

=–

For complex vector bundles over complex varieties this statement is due to Alexander Grothendieck and (Koszul-Malgrange 58), recalled for instance as (Pali 06, theorem 1). It may be understood as a special case of the Newlander-Nirenberg theorem, see (Delzant-Py 10, section 6), which also generalises the proof to infinite-dimensional vector bundles. Over Riemann surfaces, see below, the statement was highlighted in (Atiyah-Bott 83) in the context of the Narasimhan–Seshadri theorem.

The generalization from vector bundles to coherent sheaves is due to (Pali 06). In the genrality of (∞,1)-categories of chain complexes (dg-categories) of holomorphic vector bundles the statement is discussed in (Block 05).

+– {: .num_remark}

###### Remark

The equivalence in theorem \ref{KoszulMalgrangeTheorem} serves to relate a fair bit of differential geometry/differential cohomology with constructions in algebraic geometry. For instance intermediate Jacobians arise in differential geometry and quantum field theory as moduli spaces of flat connections equipped with symplectic structure and Kähler polarization, all of which in terms of algebraic geometry directly comes down moduli spaces of abelian sheaf cohomology with coefficients in the structure sheaf (and/or some variants of that, under the exponential exact sequence).

=–

- Discussion Type
- discussion topicNarasimhan–Seshadri theorem
- Category Latest Changes
- Started by Urs
- Comments 9
- Last comment by Urs
- Last Active May 21st 2014

started

*Narasimhan–Seshadri theorem*, for the moment just to collect references.

- Discussion Type
- discussion topicLoads of blank space at the end of entries
- Category Latest Changes
- Started by Tim_Porter
- Comments 15
- Last comment by Andrew Stacey
- Last Active May 21st 2014

I have just deleted a large number of dollar \ , dollar from the bottom of Blakers-Massey theorem. The effect of such is to add a large ammount of blank space at the end of the page. Was this intentional extra space for something? If not, what is causing it? I should add that I have found similar blank space before and deleted that as well.

- Discussion Type
- discussion topicHodge cohomology
- Category Latest Changes
- Started by Urs
- Comments 1
- Last comment by Urs
- Last Active May 20th 2014

added some minimum to

*Hodge cohomology*

- Discussion Type
- discussion topicfiltered homotopy colimit
- Category Latest Changes
- Started by Urs
- Comments 1
- Last comment by Urs
- Last Active May 20th 2014

since it turned out to be hard to find, I gave the discussion of filtered homotopy colimits at

*combinatorial model category*its own entry, and cross-linked:

- Discussion Type
- discussion topicCalabi-Yau cohomology
- Category Latest Changes
- Started by Urs
- Comments 2
- Last comment by Urs
- Last Active May 17th 2014

started a minimum at

*Calabi-Yau cohomology*.This is an obvious idea that must have been studied before (for $n \geq 2$) but I have had no luck with finding much detail so far.

- Discussion Type
- discussion topicgorups and gorupoids
- Category Latest Changes
- Started by Tim_Porter
- Comments 1
- Last comment by Tim_Porter
- Last Active May 17th 2014

;-). I found a typo ‘gorup’ and did a search on the n-Lab…. great fun! It is good to know others have disobient fingers!

- Discussion Type
- discussion topicF/M-theory on elliptically fibered Calabi-Yau 4-folds
- Category Latest Changes
- Started by Urs
- Comments 1
- Last comment by Urs
- Last Active May 16th 2014

am starting an entry

*F/M-theory on elliptically fibered Calabi-Yau 4-folds*So far there is mainly an Idea-section.

- Discussion Type
- discussion topicmoduli of higher lines -- table
- Category Latest Changes
- Started by Urs
- Comments 1
- Last comment by Urs
- Last Active May 16th 2014

created a survey-table-for-inclusion

and included it into the relevant entries

- Discussion Type
- discussion topicholomorphic Chern-Simons theory
- Category Latest Changes
- Started by Urs
- Comments 4
- Last comment by Urs
- Last Active May 15th 2014

Zoran,

I wanted to add a reference to

*holomorphic Chern-Simons theory*, only to realize that the entry didn't exist yet. Didn't you recently write something about holomorphic CS? I can't find it right now...

- Discussion Type
- discussion topic3d supergravity
- Category Latest Changes
- Started by Urs
- Comments 1
- Last comment by Urs
- Last Active May 14th 2014

added references to

*3d supergravity*, with brief comments, and added a paragraph on how maximally supersymmetric 3d supergravity does admit an $E_{8(8)}$-gauge field (while fluxed compactification from 11d allows only proper subgroups of the global U-duality $E_{8(8)}$ to be gauged)

- Discussion Type
- discussion topiccubical structure in M-theory
- Category Latest Changes
- Started by Urs
- Comments 2
- Last comment by Urs
- Last Active May 13th 2014

wrote an entry

*cubical structure in M-theory*.This reviews two stories from the literature, and points out that these two stories may be related.

I am not sure yet exactly how much they are related. I am asking that here on PO

- Discussion Type
- discussion topicguide to nc algebraic geometry literature
- Category Latest Changes
- Started by adeelkh
- Comments 13
- Last comment by Urs
- Last Active May 13th 2014

- I started an incomplete

* guide to noncommutative algebraic geometry literature

which is obviously missing several important papers. I will hopefully continue tomorrow. Later I will try to merge it with the existing entries.

- Discussion Type
- discussion topicinstanton
- Category Latest Changes
- Started by Urs
- Comments 10
- Last comment by Urs
- Last Active May 12th 2014

stub for instanton

- Discussion Type
- discussion topiccubical structure on a complex line bundle
- Category Latest Changes
- Started by Urs
- Comments 3
- Last comment by Urs
- Last Active May 9th 2014

started some minimum at

*cubical structure on a line bundle*

- Discussion Type
- discussion topicNilpotent ideal
- Category Latest Changes
- Started by Colin Tan
- Comments 5
- Last comment by Colin Tan
- Last Active May 8th 2014

Currently, an element x in a nonassociative algebra A is nilpotent if there exist a natural number n such that $x^n = 0$.

I want to say that a nilpotent left ideal of a ring R is a nilpotent element in the set of left ideals of R. To say that, I have to determine the structure of the set of left ideals of a ring under addition and multiplication. Wikipedia says that the set of ideals of a ring is a complete modular lattice. Is a complete modular lattice a nonassociative algebra? If not, do people talk about nilpotent elements in a lattice?

- Discussion Type
- discussion topicMizar
- Category Latest Changes
- Started by Urs
- Comments 1
- Last comment by Urs
- Last Active May 8th 2014

added to

*Mizar*a quote:One of the biggest problems that worry the developers of automated deduction systems is that their systems are not sufficiently recognized and exploited by working mathematicians. Unlike the computer algebra systems, the use of which has indeed become ubiquitous in the work of mathematicians these days, deduction systems are still seldom used. They are mostly used to formalize proofs of well-established and widely known classical theorems, the Fundamental Theorem of Algebra formalized in the systems Coq and Mizar may serve as a perfect example here. Such work, however, is not always considered to be really challenging from the viewpoint of mathematicians who are concerned with obtaining their own new results. Therefore it has been recognized as a big challenge for the deduction systems community to prove that some of the state-of-the-art systems are developed enough to cope with formalizing recent mathematics.

- Discussion Type
- discussion topicforcing in homotopy type theory
- Category Latest Changes
- Started by Urs
- Comments 6
- Last comment by Jon Beardsley
- Last Active May 4th 2014

on the off-chance that there is anyone besides me who checks MathOverflow less frequently than the $n$Forum:

there was a question on forcing in homotopy type theory. I took the liberty of sharing some thoughts.

My comment reflects topics that we have discussed here at some length already. Nevertheless, when sending this I noticed that some of these discussions need to be better reflected in the $n$Lab. And in particular better than I have commented on them for the moment.

I won’t further look into this right now as I am busy with something else. But later I’d like to come back to this.

- Discussion Type
- discussion topic(Co-)Homology QFTs?
- Category Latest Changes
- Started by sanath
- Comments 5
- Last comment by Urs
- Last Active May 3rd 2014

Let us define a (co-)homology $X$-cobordism, where $X$ is a path connected space with basepoint $*$:

**Definition:**A (co-)homology $X$ cobordism $M:\Lambda_0\to\Lambda_1$ is a cobordism $M$ such that $H^\bullet(M)=H^\bullet(X)$ for cohomology and $H_\bullet(M)=H_\bullet(X)$ for homology, where $H^\bullet(A)=\bigoplus^{\dim A}_{k\in\mathbb{N}}H^k(A)$ and $H_\bullet(A)=\bigoplus^{\dim A}_{k\in\mathbb{N}}H_k(A)$.**Definition:**A $\mathcal{C}$ valued (co-)homology QFT is a symmetric monoidal functor $(Co)HomCob(n,X)\to\mathcal{C}$, where the morphisms in $(Co)HomCob(n,X)$ are (co-)homology$X$-isomorphisms of (co-)homology $X$-cobordisms, defined as an isomorphism $\Phi:M\to M^\prime$ such that $\Phi(\partial_+ M)=M^\prime_+$ and $\Phi(\partial_- M)=M^\prime_-$.What could possible uses of such a QFT be? Can this be related to Homotopy QFTs by the Hurewicz homomorphism $\pi_k(M)\to H_k(M)$?

- Discussion Type
- discussion topichomtopytypetheory:model of type theory in an (infinity,1)-topos
- Category Latest Changes
- Started by Urs
- Comments 1
- Last comment by Urs
- Last Active May 3rd 2014

Mike kindly wrote

*model of type theory in an (infinity,1)-topos (homotopytypetheory)*with an explicit statement of how univalent Tarskian types-of-types have semantics by object classifiers in general $\infty$-toposes.I have added a brief pointer to this to some relevant $n$Lab entries: to

*homotopy type theory*, to*relation between category theory and type theory*, to*(infinity,1)-topos*and to*elementary (infinity,1)-topos*.

- Discussion Type
- discussion topictau-function, Hirota
- Category Latest Changes
- Started by zskoda
- Comments 1
- Last comment by zskoda
- Last Active May 3rd 2014

New stubs tau-function, Hirota equation and person entry Mattia Cafasso. Corrections/references to some related entries, e.g. Fredholm determinant.

- Discussion Type
- discussion topicElf, Twelf, Drölf
- Category Latest Changes
- Started by Urs
- Comments 8
- Last comment by Urs
- Last Active May 2nd 2014

- Discussion Type
- discussion topicNew page: Automaton
- Category Latest Changes
- Started by Stephen Britton
- Comments 4
- Last comment by Noam_Zeilberger
- Last Active May 2nd 2014

- There is now a new page, Automaton.

- Discussion Type
- discussion topiccohomological field theory
- Category Latest Changes
- Started by Urs
- Comments 1
- Last comment by Urs
- Last Active May 2nd 2014

created a brief entry

*cohomological field theory*and cross-linked a good bit.

- Discussion Type
- discussion topicLeech lattice
- Category Latest Changes
- Started by Urs
- Comments 1
- Last comment by Urs
- Last Active May 1st 2014

added at

*Leech lattice*a pointer to- Richard Borcherds,
*The Leech lattice and other lattices*(arXiv:math.NT/9911195)

- Richard Borcherds,

- Discussion Type
- discussion topicLong March
- Category Latest Changes
- Started by Tim_Porter
- Comments 1
- Last comment by Tim_Porter
- Last Active May 1st 2014

I created a stub at Long March as someone had started an empty entry there. For the moment it directs back to Galois theory where there is mention of the discussion at Long March, doh! I should prepare a longer entry, but do not understand the topic that well.

- Discussion Type
- discussion topiccontinued fraction
- Category Latest Changes
- Started by Todd_Trimble
- Comments 33
- Last comment by Noam_Zeilberger
- Last Active Apr 30th 2014

Wrote continued fraction, emphasizing coalgebraic aspects. More links should be inserted, and some more material needs to be filled in.

- Discussion Type
- discussion topiccomparison map between algebraic and topological K-theory
- Category Latest Changes
- Started by Urs
- Comments 4
- Last comment by Urs
- Last Active Apr 29th 2014

This used to be a super-brief paragraph at

*topological K-theory*; and now it is a slightly longer but still stubby entry*comparison map between algebraic and topological K-theory*

- Discussion Type
- discussion topicČech model structure on simplicial presheaves
- Category Latest Changes
- Started by Zhen Lin
- Comments 2
- Last comment by Urs
- Last Active Apr 26th 2014

There seem to be some misleading remarks at Čech model structure on simplicial presheaves.

Accordingly, the (∞,1)-topos presented by the Čech model structure has as its cohomology theory Čech cohomology.

Marc Hoyois seems to says the opposite: there is no deep relation between “Čech” in “Čech cohomology” and in “Čech model structure”.

[…] the corresponding Čech cover morphism .

Notice that by the discussion at model structure on simplicial presheaves - fibrant and cofibrant objects this is a morphism between cofibrant objects.

The Čech nerve is projective-cofibrant if we assume the site has pullbacks. I don’t know how to prove it otherwise. Of course, injective-cofibrancy is trivial.

this question is evidently also relevant to what the correct notion of internal ∞-groupoid may be

Based on the discussion here, it seems that the Čech model structure is

*not*site-independent, even though it can be defined on the category of simplicial*sheaves*. A very strange state of affairs…

- Discussion Type
- discussion topicsmooth spectrum
- Category Latest Changes
- Started by Urs
- Comments 4
- Last comment by Urs
- Last Active Apr 26th 2014

am starting an entry

*smooth spectrum*(in the sense of*smooth infinity-groupoid*). But nothing much there yet.

- Discussion Type
- discussion topicSO orientation of elliptic cohomology
- Category Latest Changes
- Started by Urs
- Comments 3
- Last comment by Urs
- Last Active Apr 24th 2014

minimum at

*spin orientation of Tate K-theory*, for the moment just as to record the reference and the proposition number in there (to go with this MO question)

- Discussion Type
- discussion topicreal-oriented cohomology theory
- Category Latest Changes
- Started by Urs
- Comments 2
- Last comment by Urs
- Last Active Apr 23rd 2014

started some minimum at

*real-oriented cohomology theory*

- Discussion Type
- discussion topiccongruence subgroup
- Category Latest Changes
- Started by Urs
- Comments 2
- Last comment by Urs
- Last Active Apr 22nd 2014

some basics at

*congruence subgroup*

- Discussion Type
- discussion topicquery at contravariant functor
- Category Latest Changes
- Started by Tim_Porter
- Comments 3
- Last comment by Zhen Lin
- Last Active Apr 21st 2014

Vladimir Sotirov has asked a question at contravariant functor.

- Discussion Type
- discussion topicFermat's little theorem
- Category Latest Changes
- Started by Colin Tan
- Comments 6
- Last comment by Colin Tan
- Last Active Apr 21st 2014

Stated Fermat’s little theorem.