https://arxiv.org/pdf/2004.13108.pdf PROBABILISTIC SZPIRO, BABY SZPIRO, AND EXPLICIT SZPIRO FROM MOCHIZUKI’S COROLLARY 3.12 TAYLOR DUPUY AND ANTON HILADO Date: April 30, 2020. P14 Remark 3.8.3. (1) The assertion of [SS17, pg 10] is that (3.3) is the only relation between the q-pilot and Θ-pilot degrees. The assertion of [Moc18, C14] is that [SS17, pg 10] is not what occurs in [Moc15a]. The reasoning of [SS17, pg 10] is something like what follows: P15 (2) We would like to point out that the diagram on page 10 of [SS17] is very similar to the diagram on §8.4 part 7, page 76 of the unpublished manuscript [Tan18] which Scholze and Stix were reading while preparing [SS17]. References [SS17] Peter Scholze and Jakob Stix, Why abc is still a conjecture., 2017. 1, 1, 1e, 2, 7.5.3 ( http://www.kurims.kyoto-u.ac.jp/~motizuki/IUTch-discussions-2018-03.html ) [Tan18] Fucheng Tan, Note on IUT, 2018. 1, 2 つづく
http://www.kurims.kyoto-u.ac.jp/~motizuki/Tan%20---%20Introduction%20to%20inter-universal%20Teichmuller%20theory%20(slides).pdf Introduction to Inter-universal Teichm¨uller theory Fucheng Tan RIMS, Kyoto University 2018 To my limited experiences, the following seem to be an option for people who wish to get to know IUT without spending too much time on all the details. ・ Regard the anabelian results and the general theory of Frobenioids as blackbox. ・ Proceed to read Sections 1, 2 of [EtTh], which is the basis of IUT. ・ Read [IUT-I] and [IUT-II] (briefly), so as to know the basic definitions. ・ Read [IUT-III] carefully. To make sense of the various definitions/constructions in the second half of [IUT-III], one needs all the previous definitions/results. ・ The results in [IUT-IV] were in fact discovered first. Section 1 of [IUT-IV] allows one to see the construction in [IUT-III] in a rather concrete way, hence can be read together with [IUT-III], or even before. S. Mochizuki, The ´etale theta function and its Frobenioid-theoretic manifestations. S. Mochizuki, Inter-universal Teichm¨uller Theory I, II, III, IV.
http://www.kurims.kyoto-u.ac.jp/daigakuin/Tan.pdf 教員名: 譚 福成(Tan, Fucheng) P-adic Hodge theory plays an essential role in Mochizuki's proof of Grothendieck's Anabelian Conjecture. Recently, I have been studying anabeian geometry and Mochizuki's Inter-universal Teichmuller theory, which is in certain sense a global simulation of p-adic comparison theorem.
http://www.kurims.kyoto-u.ac.jp/~bcollas/IUT/documents/RIMS-Lille%20-%20Promenade%20in%20Inter-Universal%20Teichm%C3%BCller%20Theory.pdf Research Institute for Mathematical Sciences - Kyoto University, Japan PROMENADE IN INTER-UNIVERSAL TEICHMULLER THEORY - 復元 Online Seminar - Algebraic & Arithmetic Geometry Laboratoire Paul Painleve - Universite de Lille, France Version 1 ? ε - 09/10/2020
http://www.kurims.kyoto-u.ac.jp/~bcollas/IUT/IUT-references.html Promenade in Inter-Universal Teichmuller Theory Org.: Collas (RIMS); Debes, Fresse (Lille). The Programme of the seminar contains a selection of ~30 references with respect to (1) Diophantine Geometry, (2) IUT Geometry, and (3) Anabelian Geometry. We indicate some links towards the key opuses as well as some complementary notes and proceedings.
この関係は非常に深く、リチャード・ボーチャーズ(Richard Borcherds)により示されたように、一般カッツ・ムーディリー代数とも深く関係する。この分野の仕事は、至るところで正則でカスプを持つモジュラー形式に対し、有理型でありカスプで極を持つことのできるモジュラー函数の重要性を示している。これらの仕事は、20世紀の重要な研究の対象となった。 0013132人目の素数さん2021/02/07(日) 23:10:55.67ID:1q1vuYYohttps://en.wikipedia.org/wiki/Belyi%27s_theorem#Belyi_functions Belyi's theorem In mathematics, Belyi's theorem on algebraic curves states that any non-singular algebraic curve C, defined by algebraic number coefficients, represents a compact Riemann surface which is a ramified covering of the Riemann sphere, ramified at three points only.
This is a result of G. V. Belyi from 1979. At the time it was considered surprising, and it spurred Grothendieck to develop his theory of dessins d'enfant, which describes nonsingular algebraic curves over the algebraic numbers using combinatorial data.
Contents 1 Quotients of the upper half-plane 2 Belyi functions 3 Applications
Quotients of the upper half-plane It follows that the Riemann surface in question can be taken to be H/Γ with H the upper half-plane and Γ of finite index in the modular group, compactified by cusps. Since the modular group has non-congruence subgroups, it is not the conclusion that any such curve is a modular curve.
Belyi functions A Belyi function is a holomorphic map from a compact Riemann surface S to the complex projective line P1(C) ramified only over three points, which after a Mobius transformation may be taken to be {\displaystyle \{0,1,\infty \}}\{0,1,\infty \}. Belyi functions may be described combinatorially by dessins d'enfants.
Belyi functions and dessins d'enfants ? but not Belyi's theorem ? date at least to the work of Felix Klein; he used them in his article (Klein 1879) to study an 11-fold cover of the complex projective line with monodromy group PSL(2,11).[1]
Applications Belyi's theorem is an existence theorem for Belyi functions, and has subsequently been much used in the inverse Galois problem. 0015132人目の素数さん2021/02/07(日) 23:12:30.85ID:1q1vuYYohttps://en.wikipedia.org/wiki/Dessin_d%27enfant Dessin d'enfant
In mathematics, a dessin d'enfant is a type of graph embedding used to study Riemann surfaces and to provide combinatorial invariants for the action of the absolute Galois group of the rational numbers. The name of these embeddings is French for a "child's drawing"; its plural is either dessins d'enfant, "child's drawings", or dessins d'enfants, "children's drawings". A dessin d'enfant is a graph, with its vertices colored alternately black and white, embedded in an oriented surface that, in many cases, is simply a plane. For the coloring to exist, the graph must be bipartite. The faces of the embedding must be topological disks. The surface and the embedding may be described combinatorially using a rotation system, a cyclic order of the edges surrounding each vertex of the graph that describes the order in which the edges would be crossed by a path that travels clockwise on the surface in a small loop around the vertex.
Any dessin can provide the surface it is embedded in with a structure as a Riemann surface. It is natural to ask which Riemann surfaces arise in this way. The answer is provided by Belyi's theorem, which states that the Riemann surfaces that can be described by dessins are precisely those that can be defined as algebraic curves over the field of algebraic numbers. The absolute Galois group transforms these particular curves into each other, and thereby also transforms the underlying dessins.
For a more detailed treatment of this subject, see Schneps (1994) or Lando & Zvonkin (2004).
Contents 1 History 1.1 19th century 1.2 20th century 2 Riemann surfaces and Belyi pairs
History 19th century Early proto-forms of dessins d'enfants appeared as early as 1856 in the icosian calculus of William Rowan Hamilton;[1] in modern terms, these are Hamiltonian paths on the icosahedral graph.
Recognizable modern dessins d'enfants and Belyi functions were used by Felix Klein (1879). Klein called these diagrams Linienzuge (German, plural of Linienzug "line-track", also used as a term for polygon); he used a white circle for the preimage of 0 and a '+' for the preimage of 1, rather than a black circle for 0 and white circle for 1 as in modern notation.[2] He used these diagrams to construct an 11-fold cover of the Riemann sphere by itself, with monodromy group PSL(2,11), following earlier constructions of a 7-fold cover with monodromy PSL(2,7) connected to the Klein quartic in (Klein 1878?1879a, 1878?1879b). These were all related to his investigations of the geometry of the quintic equation and the group A5 ? PSL(2,5), collected in his famous 1884/88 Lectures on the Icosahedron. The three surfaces constructed in this way from these three groups were much later shown to be closely related through the phenomenon of trinity.
20th century Dessins d'enfant in their modern form were then rediscovered over a century later and named by Alexander Grothendieck in 1984 in his Esquisse d'un Programme.[3] Zapponi (2003) quotes Grothendieck regarding his discovery of the Galois action on dessins d'enfants:
This discovery, which is technically so simple, made a very strong impression on me, and it represents a decisive turning point in the course of my reflections, a shift in particular of my centre of interest in mathematics, which suddenly found itself strongly focused. I do not believe that a mathematical fact has ever struck me quite so strongly as this one, nor had a comparable psychological impact. This is surely because of the very familiar, non-technical nature of the objects considered, of which any child’s drawing scrawled on a bit of paper (at least if the drawing is made without lifting the pencil) gives a perfectly explicit example. To such a dessin we find associated subtle arithmetic invariants, which are completely turned topsy-turvy as soon as we add one more stroke.
Part of the theory had already been developed independently by Jones & Singerman (1978) some time before Grothendieck. They outline the correspondence between maps on topological surfaces, maps on Riemann surfaces, and groups with certain distinguished generators, but do not consider the Galois action. Their notion of a map corresponds to a particular instance of a dessin d'enfant. Later work by Bryant & Singerman (1985) extends the treatment to surfaces with a boundary.
https://eow.alc.co.jp/search?q=modulus modulus 名 《物理》係数、率 《数学》法、対数係数、絶対値◆【略】mod. 発音[US] m??d??l?s | [UK] m??djul?s、カナ[US]モジュラス、[UK]モデュラス、 0019132人目の素数さん2021/02/13(土) 13:20:18.51ID:wXktx3pjhttps://en.wikipedia.org/wiki/Belyi%27s_theorem Belyi's theorem Contents 1 Quotients of the upper half-plane 2 Belyi functions 3 Applications Applications Belyi's theorem is an existence theorem for Belyi functions, and has subsequently been much used in the inverse Galois problem.
https://en.wikipedia.org/wiki/Dessin_d%27enfant Dessin d'enfant Contents 1 History 1.1 19th century 1.2 20th century 2 Riemann surfaces and Belyi pairs 3 Maps and hypermaps 4 Regular maps and triangle groups 5 Trees and Shabat polynomials 6 The absolute Galois group and its invariants
Contents 1 Examples 2 Problems 3 Some general results
Problems No direct description is known for the absolute Galois group of the rational numbers. In this case, it follows from Belyi's theorem that the absolute Galois group has a faithful action on the dessins d'enfants of Grothendieck (maps on surfaces), enabling us to "see" the Galois theory of algebraic number fields. 0020132人目の素数さん2021/02/13(土) 13:41:13.38ID:4TALI0LV コピペは続くよどこまでも 0021132人目の素数さん2021/02/13(土) 14:11:15.66ID:4eb0VVkt どうせなら、翻訳しよう
In mathematics, a pro-p group (for some prime number p) is a profinite group {\displaystyle G}G such that for any open normal subgroup {\displaystyle N\triangleleft G}N\triangleleft G the quotient group {\displaystyle G/N}G/N is a p-group. Note that, as profinite groups are compact, the open subgroups are exactly the closed subgroups of finite index, so that the discrete quotient group is always finite.
Alternatively, one can define a pro-p group to be the inverse limit of an inverse system of discrete finite p-groups.
The best-understood (and historically most important) class of pro-p groups is the p-adic analytic groups: groups with the structure of an analytic manifold over {\displaystyle \mathbb {Q} _{p}}\mathbb {Q} _{p} such that group multiplication and inversion are both analytic functions. The work of Lubotzky and Mann, combined with Michel Lazard's solution to Hilbert's fifth problem over the p-adic numbers, shows that a pro-p group is p-adic analytic if and only if it has finite rank, i.e. there exists a positive integer {\displaystyle r}r such that any closed subgroup has a topological generating set with no more than {\displaystyle r}r elements. More generally it was shown that a finitely generated profinite group is a compact p-adic Lie group if and only if it has an open subgroup that is a uniformly powerful pro-p-group.
The Coclass Theorems have been proved in 1994 by A. Shalev and independently by C. R. Leedham-Green. Theorem D is one of these theorems and asserts that, for any prime number p and any positive integer r, there exist only finitely many pro-p groups of coclass r. This finiteness result is fundamental for the classification of finite p-groups by means of directed coclass graphs. 0027132人目の素数さん2021/02/19(金) 08:23:53.43ID:G/gMneGZ>>24 ありがとう ご苦労様 0028132人目の素数さん2021/02/19(金) 09:26:21.86ID:46Fge3L7>>25 そもそも射影系が分かってないんじゃ意味ないぞ
スキーム アフィンスキームの張り合わせとしてえられるような局所環付き空間は前スキームまたは概型(スキーム)とよばれる。グロタンディークのEGAやマンフォードの「Red Book」など初期の文献には概型/スキームという用語で前スキームのうちで特に点の分離性を満たすものをさしているものもある。 0032132人目の素数さん2021/02/23(火) 23:29:48.30ID:RLePkY5e 局所は、局所化:環に乗法逆元を機械的に添加する 局所環:In practice, a commutative local ring often arises as the result of the localization of a ring at a prime ideal. The English term local ring is due to Zariski.[2]
https://ja.wikipedia.org/wiki/%E7%92%B0%E3%81%AE%E5%B1%80%E6%89%80%E5%8C%96 環の局所化(きょくしょか、英: localization)あるいは分数環 (ring of fraction)、商環 (ring of quotient)[注 1] は、環に乗法逆元を機械的に添加する方法である。すなわち、環 R とその部分集合 S が与えられたとき、環 R' と R から R' への環準同型を構成して、S の準同型像が R' における単元(可逆元)のみからなるようにする。さらに、R' が「可能な限りで最良な」あるいは「最も一般な」ものとなるようにするということを考える(こういった状況はふつうは普遍性によって表されるべきものである)。環 R の部分集合 S による局所化は S−1R で表され、あるいは S が素イデアル {p} の補集合であるときには R_ {p}} で表される。S−1R のことを RS と表すこともあるが、通常混乱の恐れはない。
局所化は完備化と重要な関係があり、環を局所化すると完備になるということがよくある。
用語について 「局所化」の名の起源は代数幾何学にある。R はある幾何学的対象(代数多様体)の上で定義された函数環とする。この多様体を点 p の近傍で「局所的に」調べようとするならば、p の近傍で 0 でないような函数全体の成す集合 S を考えることになる。その意味で、R を S に関して局所化して得られる環 S−1R は p の近傍における V の挙動についての情報のみをふくんでいる(局所環も参照)。
例 整数環を Z, 有理数体を Q と表す。
R = Z のとき、積閉集合 S = Z − {0} による局所化は S−1R = Q である。
https://en.wikipedia.org/wiki/Local_ring In abstract algebra, more specifically ring theory, local rings are certain rings that are comparatively simple, and serve to describe what is called "local behaviour", in the sense of functions defined on varieties or manifolds, or of algebraic number fields examined at a particular place, or prime. Local algebra is the branch of commutative algebra that studies commutative local rings and their modules.
In practice, a commutative local ring often arises as the result of the localization of a ring at a prime ideal.
The concept of local rings was introduced by Wolfgang Krull in 1938 under the name Stellenringe.[1] The English term local ring is due to Zariski.[2]
Examples All fields (and skew fields) are local rings, since {0} is the only maximal ideal in these rings. A nonzero ring in which every element is either a unit or nilpotent is a local ring. 0033132人目の素数さん2021/02/26(金) 10:41:04.06ID:/iWCqc/x 田口 雄一郎先生、結構面白い
http://www.math.titech.ac.jp/~taguchi/nihongo/abc.html abc予想の話 ( 昔、北大理学部 HP の「サイエンストピックス」に掲載されたもの ) 田口 雄一郎 http://www.math.titech.ac.jp/~taguchi/nihongo/bunsho.html Yuichiro TAGUCHI 0035132人目の素数さん2021/02/27(土) 23:24:57.49ID:f+hU2HEr>>34 メモ https://en.wikipedia.org/wiki/Klein_quartic Klein quartic In hyperbolic geometry, the Klein quartic, named after Felix Klein, is a compact Riemann surface of genus 3 with the highest possible order automorphism group for this genus, namely order 168 orientation-preserving automorphisms, and 336 automorphisms if orientation may be reversed. As such, the Klein quartic is the Hurwitz surface of lowest possible genus; see Hurwitz's automorphisms theorem. Its (orientation-preserving) automorphism group is isomorphic to PSL(2, 7), the second-smallest non-abelian simple group. The quartic was first described in (Klein 1878b).
Closed and open forms It is important to distinguish two different forms of the quartic. The closed quartic is what is generally meant in geometry; topologically it has genus 3 and is a compact space. The open or "punctured" quartic is of interest in number theory; topologically it is a genus 3 surface with 24 punctures, and geometrically these punctures are cusps. The open quartic may be obtained (topologically) from the closed quartic by puncturing at the 24 centers of the tiling by regular heptagons, as discussed below. The open and closed quartics have different metrics, though they are both hyperbolic and complete[1] – geometrically, the cusps are "points at infinity", not holes, hence the open quartic is still complete.
Affine quartic The above is a tiling of the projective quartic (a closed manifold); the affine quartic has 24 cusps (topologically, punctures), which correspond to the 24 vertices of the regular triangular tiling, or equivalently the centers of the 24 heptagons in the heptagonal tiling, and can be realized as follows.
Considering the action of SL(2, R) on the upper half-plane model H2 of the hyperbolic plane by Möbius transformations, the affine Klein quartic can be realized as the quotient Γ(7)\H2. (Here Γ(7) is the congruence subgroup of SL(2, Z) consisting of matrices that are congruent to the identity matrix when all entries are taken modulo 7.)
Dessin d'enfants The dessin d'enfant on the Klein quartic associated with the quotient map by its automorphism group (with quotient the Riemann sphere) is precisely the 1-skeleton of the order-3 heptagonal tiling.[10] That is, the quotient map is ramified over the points 0, 1728, and ∞; dividing by 1728 yields a Belyi function (ramified at 0, 1, and ∞), where the 56 vertices (black points in dessin) lie over 0, the midpoints of the 84 edges (white points in dessin) lie over 1, and the centers of the 24 heptagons lie over infinity. The resulting dessin is a "platonic" dessin, meaning edge-transitive and "clean" (each white point has valence 2).
https://en.wikipedia.org/wiki/Klein_quadric Klein quadric In mathematics, the lines of a 3-dimensional projective space, S, can be viewed as points of a 5-dimensional projective space, T. In that 5-space, the points that represent each line in S lie on a quadric, Q known as the Klein quadric.
If the underlying vector space of S is the 4-dimensional vector space V, then T has as the underlying vector space the 6-dimensional exterior square Λ2V of V. The line coordinates obtained this way are known as Plücker coordinates. 以上 0038132人目の素数さん2021/02/27(土) 23:36:36.38ID:f+hU2HEr>>37
Punctured spheres These statements are clarified by considering the type of a Riemann sphere {\displaystyle {\widehat {\mathbf {C} }}}\widehat{\mathbf{C}} with a number of punctures. With no punctures, it is the Riemann sphere, which is elliptic. With one puncture, which can be placed at infinity, it is the complex plane, which is parabolic. With two punctures, it is the punctured plane or alternatively annulus or cylinder, which is parabolic. With three or more punctures, it is hyperbolic – compare pair of pants. One can map from one puncture to two, via the exponential map (which is entire and has an essential singularity at infinity, so not defined at infinity, and misses zero and infinity), but all maps from zero punctures to one or more, or one or two punctures to three or more are constant.
Isometries of Riemann surfaces The isometry group of a uniformized Riemann surface (equivalently, the conformal automorphism group) reflects its geometry: ・the isometry group of the plane is the subgroup fixing infinity, and of the punctured plane is the subgroup leaving invariant the set containing only infinity and zero: either fixing them both, or interchanging them (1/z). 0039132人目の素数さん2021/02/28(日) 08:21:52.42ID:c9K39yvS>>24 ありがとう (追加) https://en.wikipedia.org/wiki/Dessin_d%27enfant Dessin d'enfant Contents 1 History 1.1 19th century 1.2 20th century 2 Riemann surfaces and Belyi pairs 3 Maps and hypermaps 4 Regular maps and triangle groups 5 Trees and Shabat polynomials 6 The absolute Galois group and its invariants
Riemann surfaces and Belyi pairs Each triangle in the triangulation has three vertices labeled 0 (for the black points), 1 (for the white points), or ∞. For each triangle, substitute a half-plane, either the upper half-plane for a triangle that has 0, 1, and ∞ in counterclockwise order or the lower half-plane for a triangle that has them in clockwise order, and for every adjacent pair of triangles glue the corresponding half-planes together along the portion of their boundaries indicated by the vertex labels. The resulting Riemann surface can be mapped to the Riemann sphere by using the identity map within each half-plane. Thus, the dessin d'enfant formed from f is sufficient to describe f itself up to biholomorphism. However, this construction identifies the Riemann surface only as a manifold with complex structure; it does not construct an embedding of this manifold as an algebraic curve in the complex projective plane, although such an embedding always exists.
The same construction applies more generally when X is any Riemann surface and f is a Belyi function; that is, a holomorphic function f from X to the Riemann sphere having only 0, 1, and ∞ as critical values. A pair (X, f) of this type is known as a Belyi pair. From any Belyi pair (X, f) one can form a dessin d'enfant, drawn on the surface X, that has its black points at the preimages f-1(0) of 0, its white points at the preimages f-1(1) of 1, and its edges placed along the preimages f-1([0, 1]) of the line segment [0, 1]. Conversely, any dessin d'enfant on any surface X can be used to define gluing instructions for a collection of halfspaces that together form a Riemann surface homeomorphic to X; mapping each halfspace by the identity to the Riemann sphere produces a Belyi function f on X, and therefore leads to a Belyi pair (X, f). Any two Belyi pairs (X, f) that lead to combinatorially equivalent dessins d'enfants are biholomorphic, and Belyi's theorem implies that, for any compact Riemann surface X defined over the algebraic numbers, there are a Belyi function f and a dessin d'enfant that provides a combinatorial description of both X and f.
Maps and hypermaps A vertex in a dessin has a graph-theoretic degree, the number of incident edges, that equals its degree as a critical point of the Belyi function.
Thus, any embedding of a graph in a surface in which each face is a disk (that is, a topological map) gives rise to a dessin by treating the graph vertices as black points of a dessin, and placing white points at the midpoint of each embedded graph edge. If a map corresponds to a Belyi function f, its dual map (the dessin formed from the preimages of the line segment [1, ∞]) corresponds to the multiplicative inverse 1/f.[5]
A dessin that is not clean can be transformed into a clean dessin in the same surface, by recoloring all of its points as black and adding new white points on each of its edges. The corresponding transformation of Belyi pairs is to replace a Belyi function β by the pure Belyi function γ = 4β(1 - β).
The absolute Galois group and its invariants The two choices of a lead to two Belyi functions f1 and f2. These functions, though closely related to each other, are not equivalent, as they are described by the two nonisomorphic trees shown in the figure.
However, as these polynomials are defined over the algebraic number field Q(√21), they may be transformed by the action of the absolute Galois group Γ of the rational numbers. An element of Γ that transforms √21 to -√21 will transform f1 into f2 and vice versa, and thus can also be said to transform each of the two trees shown in the figure into the other tree.
More generally, due to the fact that the critical values of any Belyi function are the pure rationals 0, 1, and ∞, these critical values are unchanged by the Galois action, so this action takes Belyi pairs to other Belyi pairs. One may define an action of Γ on any dessin d'enfant by the corresponding action on Belyi pairs; this action, for instance, permutes the two trees shown in the figure.
Due to Belyi's theorem, the action of Γ on dessins is faithful (that is, every two elements of Γ define different permutations on the set of dessins),[10] so the study of dessins d'enfants can tell us much about Γ itself.
The two Belyi functions f1 and f2 of this example are defined over the field of moduli, but there exist dessins for which the field of definition of the Belyi function must be larger than the field of moduli.[11] (引用終り) 以上 0042132人目の素数さん2021/02/28(日) 16:01:49.39ID:c9K39yvS メモ https://en.wikipedia.org/wiki/Algebraic_stack Algebraic stack
In mathematics, an algebraic stack is a vast generalization of algebraic spaces, or schemes, which are foundational for studying moduli theory. Many moduli spaces are constructed using techniques specific to algebraic stacks, such as Artin's representability theorem, which is used to construct the moduli space of pointed algebraic curves {\displaystyle {\mathcal {M}}_{g,n}}{\mathcal {M}}_{{g,n}} and the moduli stack of elliptic curves. Originally, they were introduced by Grothendieck[1] to keep track of automorphisms on moduli spaces, a technique which allows for treating these moduli spaces as if their underlying schemes or algebraic spaces are smooth. But, through many generalizations the notion of algebraic stacks was finally discovered by Michael Artin.[2]
http://www.math.chuo-u.ac.jp/morita_newser.htm 森田茂之氏による特別講演:新シリーズ(ENCOUNTERwithMATHEMATICS番外編)中央大学 2013年秋から、全体を仕切りなおして新シリーズを開始します. http://www.math.chuo-u.ac.jp/LN_in_Chuo_v11.pdf トポロジーの課題探訪 ―特性類と不変量を中心として― 森田茂之 2013 年 10 月 9 日- 0046132人目の素数さん2021/03/21(日) 06:55:19.90ID:00ruIs7L メモ https://en.wikipedia.org/wiki/Perverse_sheaf Perverse sheaf The mathematical term perverse sheaves refers to a certain abelian category associated to a topological space X, which may be a real or complex manifold, or a more general topologically stratified space, usually singular. This concept was introduced in the thesis of Zoghman Mebkhout, gaining more popularity after the (independent) work of Joseph Bernstein, Alexander Beilinson, and Pierre Deligne (1982) as a formalisation of the Riemann-Hilbert correspondence, which related the topology of singular spaces (intersection homology of Mark Goresky and Robert MacPherson) and the algebraic theory of differential equations (microlocal calculus and holonomic D-modules of Joseph Bernstein, Masaki Kashiwara and Takahiro Kawai). It was clear from the outset that perverse sheaves are fundamental mathematical objects at the crossroads of algebraic geometry, topology, analysis and differential equations. They also play an important role in number theory, algebra, and representation theory. The properties characterizing perverse sheaves already appeared in the 75's paper of Kashiwara on the constructibility of solutions of holonomic D-modules.
Contents 1 Preliminary remarks 2 Definition and examples 3 Properties 4 Applications 5 String Theory
String Theory Massless fields in superstring compactifications have been identified with cohomology classes on the target space (i.e. four-dimensional Minkowski space with a six-dimensional Calabi-Yau (CY) manifold). The determination of the matter and interaction content requires a detailed analysis of the (co)homology of these spaces: nearly all massless fields in the effective physics model are represented by certain (co)homology elements. However, a troubling consequence occurs when the target space is singular. A singular target space means that only the CY manifold is singular as Minkowski space is smooth. Such a singular CY manifold is called a conifold as it is a CY manifold that admits conical singularities. Andrew Strominger observed (A. Strominger, 1995) that conifolds correspond to massless blackholes.
These singular target spaces, i.e. conifolds, correspond to certain mild degenerations of algebraic varieties which appear in a large class of supersymmetric theories, including superstring theory (E. Witten, 1982).
In the winter of 2002, T. Hubsch and A. Rahman met with R.M. Goresky to discuss this obstruction and in discussions between R.M. Goresky and R. MacPherson, R. MacPherson made the observation that there was such a perverse sheaf that could have the cohomology that satisfied Hubsch's conjecture and resolved the obstruction. R.M. Goresky and T. Hubsch advised A. Rahman's Ph.D. dissertation on the construction of a self-dual perverse sheaf (A. Rahman, 2009) using the zig-zag construction of MacPherson-Vilonen (R. MacPherson & K. Vilonen, 1986). This perverse sheaf proved the Hübsch conjecture for isolated conic singularities, satisfied Poincarè duality, and aligned with some of the properties of the Kähler package.
Satisfaction of all of the Kähler package by this Perverse sheaf for higher codimension strata is still an open problem.
https://arxiv.org/pdf/1806.06129.pdf CATEGORICAL NOTIONS OF FIBRATION FOSCO LOREGIAN AND EMILY RIEHL Date: Original version December 20, 2010; revised version February 19, 2019.
https://en.wikipedia.org/wiki/Fibred_category Fibred categories (or fibered categories) are abstract entities in mathematics used to provide a general framework for descent theory. Similar setups appear in various guises in mathematics, in particular in algebraic geometry, which is the context in which fibred categories originally appeared. Fibered categories are used to define stacks, which are fibered categories (over a site) with "descent". Fibrations also play an important role in categorical semantics of type theory, and in particular that of dependent type theories. Fibred categories were introduced by Alexander Grothendieck (1959, 1971), and developed in more detail by Jean Giraud (1964, 1971). 0050132人目の素数さん2021/03/26(金) 07:30:20.63ID:tYykNeNT>>49 >Fibred categories (or fibered categories) are abstract entities in mathematics used to provide a general framework for descent theory.
追加 https://en.wikipedia.org/wiki/Descent_(mathematics) Descent (mathematics) In mathematics, the idea of descent extends the intuitive idea of 'gluing' in topology. Since the topologists' glue is the use of equivalence relations on topological spaces, the theory starts with some ideas on identification.
Contents 1 Descent of vector bundles 2 History 3 Fully faithful descent
Descent of vector bundles
Therefore, by going to a more abstract level one can eliminate the combinatorial side (that is, leave out the indices) and get something that makes sense for p not of the special form of covering with which we began. This then allows a category theory approach: what remains to do is to re-express the gluing conditions.
History The ideas were developed in the period 1955–1965 (which was roughly the time at which the requirements of algebraic topology were met but those of algebraic geometry were not). From the point of view of abstract category theory the work of comonads of Beck was a summation of those ideas; see Beck's monadicity theorem.
The difficulties of algebraic geometry with passage to the quotient are acute. The urgency (to put it that way) of the problem for the geometers accounts for the title of the 1959 Grothendieck seminar TDTE on theorems of descent and techniques of existence (see FGA) connecting the descent question with the representable functor question in algebraic geometry in general, and the moduli problem in particular. 0051132人目の素数さん2021/03/29(月) 23:34:59.52ID:jhylP48U 「ライプニッツは間違っていたのか?」 「ラインハートは間違っていたのか?」
米田埋め込みとは,任意の局所小圏 C を C 上の前層 presheaf(Cop から Set への関手圏)に埋め込む関 手である.本稿では関手のいくつかの性質の定義を導入し,米田埋め込みを定義する.そしてそれが実際に埋 め込みになっていることを確認する.米田埋め込みとは直接関係はないが,第 1 節では圏同値の二つの定義を 紹介し,それらの定義が等しいことを確認する.
Antitone Galois connections Galois theory The motivating example comes from Galois theory: suppose L/K is a field extension. Let A be the set of all subfields of L that contain K, ordered by inclusion ⊆. If E is such a subfield, write Gal(L/E) for the group of field automorphisms of L that hold E fixed. Let B be the set of subgroups of Gal(L/K), ordered by inclusion ⊆. For such a subgroup G, define Fix(G) to be the field consisting of all elements of L that are held fixed by all elements of G. Then the maps E → Gal(L/E) and G → Fix(G) form an antitone Galois connection.
7 Connection to category theory 8 Applications in the theory of programming
Contents 1 In the school of Grothendieck 2 From pure category theory to categorical logic 3 Position of topos theory 4 Summary
In the school of Grothendieck During the latter part of the 1950s, the foundations of algebraic geometry were being rewritten; and it is here that the origins of the topos concept are to be found. At that time the Weil conjectures were an outstanding motivation to research. As we now know, the route towards their proof, and other advances, lay in the construction of etale cohomology.
Summary The topos concept arose in algebraic geometry, as a consequence of combining the concept of sheaf and closure under categorical operations. It plays a certain definite role in cohomology theories. A 'killer application' is etale cohomology.
The subsequent developments associated with logic are more interdisciplinary. They include examples drawing on homotopy theory (classifying toposes). They involve links between category theory and mathematical logic, and also (as a high-level, organisational discussion) between category theory and theoretical computer science based on type theory. Granted the general view of Saunders Mac Lane about ubiquity of concepts, this gives them a definite status. The use of toposes as unifying bridges in mathematics has been pioneered by Olivia Caramello in her 2017 book.[1]
References Caramello, Olivia (2017). Theories, Sites, Toposes: Relating and studying mathematical theories through topos-theoretic `bridges. Oxford University Press. doi:10.1093/oso/9780198758914.001.0001. ISBN 9780198758914. 0058132人目の素数さん2021/04/10(土) 09:11:58.29ID:BBK6b/st Category Theory Brief Historical Sketch
1. General Definitions, Examples and Applications 1.1 Definitions 1.2 Examples 1.3 Fundamental Concepts of the Theory 2. Brief Historical Sketch 3. Philosophical Significance Bibliography Academic Tools Other Internet Resources Related Entries
2. Brief Historical Sketch It is difficult to do justice to the short but intricate history of the field. In particular it is not possible to mention all those who have contributed to its rapid development. With this word of caution out of the way, we will look at some of the main historical threads.
Categories, functors, natural transformations, limits and colimits appeared almost out of nowhere in a paper by Eilenberg & Mac?Lane (1945) entitled “General Theory of Natural Equivalences.” We say “almost,” because their earlier paper (1942) contains specific functors and natural transformations at work, limited to groups. A desire to clarify and abstract their 1942 results led Eilenberg & Mac?Lane to devise category theory. The central notion at the time, as their title indicates, was that of natural transformation. In order to give a general definition of the latter, they defined functor, borrowing the term from Carnap, and in order to define functor, they borrowed the word ‘category’ from the philosophy of Aristotle, Kant, and C. S. Peirce, but redefining it mathematically. 0059132人目の素数さん2021/04/10(土) 11:36:08.97ID:BBK6b/st メモ 下記 誘(いざな)い 《拡大版》 なかなか良いね http://www.kurims.kyoto-u.ac.jp/~motizuki/travel-japanese.html 望月 出張講演 http://www.kurims.kyoto-u.ac.jp/~motizuki/Uchuusai%20Taihimyuuraa%20riron%20he%20no%20izanai%20(kakudaiban).pdf 望月 出張講演 [13] 宇宙際タイヒミューラー理論への誘(いざな)い 《拡大版》 (東京大学 2013年06月) PDF
過去の論文のレベルでいうと、絶対遠アーベル幾何やエタール・テータ関数の様々な剛性性質に関する ・ Semi-graphs of Anabelioids ・ The Etale Theta Function ... ・ The Geometry of Frobenioids I, II ・ Topics in Absolute Anab. Geo. III の結果や理論を適用することによって主定理を帰結する: 主定理: θ-link の 左辺 に対して、軽微な不定性を除いて、右辺 の「異質」な環構造 しか用いない言葉により、明示的なアルゴリズム による記述を与えることができる。
In combinatorial mathematics, LCF notation or LCF code is a notation devised by Joshua Lederberg, and extended by H. S. M. Coxeter and Robert Frucht, for the representation of cubic graphs that contain a Hamiltonian cycle.[2][3] The cycle itself includes two out of the three adjacencies for each vertex, and the LCF notation specifies how far along the cycle each vertex's third neighbor is. A single graph may have multiple different representations in LCF notation.
LCF notation is a concise and convenient notation devised by Joshua Lederberg (winner of the 1958 Nobel Prize in Physiology and Medicine) for the representation of cubic Hamiltonian graphs (Lederberg 1965). The notation was subsequently modified by Frucht (1976) and Coxeter et al. (1981), and hence was dubbed "LCF notation" by Frucht (1976). Pegg (2003) used the notation to describe many of the cubic symmetric graphs. The notation only applies to Hamiltonian graphs, since it achieves its symmetry and conciseness by placing a Hamiltonian cycle in a circular embedding and then connecting specified pairs of nodes with edges.