Rational Points on Modular Elliptic Curves Henri Darmon
Total Page:16
File Type:pdf, Size:1020Kb
Load more
Recommended publications
-
Stark-Heegner Points Course and Student Project Description Arizona Winter School 2011 Henri Darmon and Victor Rotger
Stark-Heegner points Course and Student Project description Arizona Winter School 2011 Henri Darmon and Victor Rotger 1 Heegner points and Stark-Heegner points 1.1 Heegner points Let E=Q be an elliptic curve over the field of rational numbers, of conductor N. Thanks to the proof of the Shimura-Taniyama conjecture, the curve E is known to be modular, i.e., P1 n there is a normalised cuspidal newform f = n=1 an(f)q of weight 2 on Γ0(N) satisfying L(E; s) = L(f; s); (1) where 1 Y −s 1−2s −1 X −s L(E; s) = (1 − ap(E)p + δpp ) = an(E)n (2) p prime n=1 is the Hasse-Weil L-series attached to E, whose coefficients with prime index are given by the formula 8 > (p + 1 − jE(Fp)j; 1) if p - N; <> (1; 0) if E has split multiplicative reduction at p; (ap(E); δp) = > (−1; 0) if E has non-split multiplicative reduction at p; :> (0; 0) if E has additive reduction at p, i.e., p2jN; and 1 X −s L(f; s) = an(f)n (3) n=1 is the Hecke L-series attached to the eigenform f. Hecke's theory shows that L(f; s) has an Euler product expansion identical to (2), and also that it admits an integral representation as a Mellin transform of f. This extends L(f; s) analytically to the whole complex plane and shows that it satisfies a functional equation relating its values at s and 2 − s. -
(Elliptic Modular Curves) JS Milne
Modular Functions and Modular Forms (Elliptic Modular Curves) J.S. Milne Version 1.30 April 26, 2012 This is an introduction to the arithmetic theory of modular functions and modular forms, with a greater emphasis on the geometry than most accounts. BibTeX information: @misc{milneMF, author={Milne, James S.}, title={Modular Functions and Modular Forms (v1.30)}, year={2012}, note={Available at www.jmilne.org/math/}, pages={138} } v1.10 May 22, 1997; first version on the web; 128 pages. v1.20 November 23, 2009; new style; minor fixes and improvements; added list of symbols; 129 pages. v1.30 April 26, 2010. Corrected; many minor revisions. 138 pages. Please send comments and corrections to me at the address on my website http://www.jmilne.org/math/. The photograph is of Lake Manapouri, Fiordland, New Zealand. Copyright c 1997, 2009, 2012 J.S. Milne. Single paper copies for noncommercial personal use may be made without explicit permission from the copyright holder. Contents Contents 3 Introduction ..................................... 5 I The Analytic Theory 13 1 Preliminaries ................................. 13 2 Elliptic Modular Curves as Riemann Surfaces . 25 3 Elliptic Functions ............................... 41 4 Modular Functions and Modular Forms ................... 48 5 Hecke Operators ............................... 68 II The Algebro-Geometric Theory 89 6 The Modular Equation for 0.N / ...................... 89 7 The Canonical Model of X0.N / over Q ................... 93 8 Modular Curves as Moduli Varieties ..................... 99 9 Modular Forms, Dirichlet Series, and Functional Equations . 104 10 Correspondences on Curves; the Theorem of Eichler-Shimura . 108 11 Curves and their Zeta Functions . 112 12 Complex Multiplication for Elliptic Curves Q . -
PRIMITIVE SOLUTIONS to X2 + Y3 = Z10 1. Introduction We Say a Triple
PRIMITIVE SOLUTIONS TO x2 + y3 = z10 DAVID BROWN Abstract. We classify primitive integer solutions to x2 + y3 = z10. The technique is to combine modular methods at the prime 5, number field enumeration techniques in place of modular methods at the prime 2, Chabauty techniques for elliptic curves over number fields, and local methods. 1. Introduction We say a triple (s; t; u) of integers is primitive if gcd(s; t; u) = 1. For a; b; c ≥ 3 the equation xa + yb = zc is expected to have no primitive integer solutions with xyz 6= 0, while for n ≤ 9 the equation x2 + y3 = zn has lots of such solutions; see for example [PSS07] for the case n = 7 and a review of previous work on generalized Fermat equations. The `next' equation to solve is x2 + y3 = z10 { it is the first of the form x2 + y3 = zn expected to have no non-obvious solutions. Theorem 1.1. The primitive integer solutions to x2 + y3 = z10 are the 10 triples (±1; 1; 0); (±1; 0; 1); ±(0; 1; 1); (±3; −2; ±1): It is clear that the only primitive solutions with xyz = 0 are the six above. To ease notation we set S(Z) = f(a; b; c): a2 + b3 = c10 j (a; b; c) is primitiveg. One idea is to use Edwards's parameterization of x2 +y3 = z5. His thesis [Edw04] produces a list of 27 degree 12 polynomials fi 2 Z[x; y] such that if (x; y; z) is such a primitive triple, then there exist i; s; t 2 Z such that z = fi(s; t) and similar polynomials for x and y. -
Elliptic Curves, Modularity, and Fermat's Last Theorem
Elliptic curves, modularity, and Fermat's Last Theorem For background and (most) proofs, we refer to [1]. 1 Weierstrass models Let K be any field. For any a1; a2; a3; a4; a6 2 K consider the plane projective curve C given by the equation 2 2 3 2 2 3 y z + a1xyz + a3yz = x + a2x z + a4xz + a6z : (1) An equation as above is called a Weierstrass equation. We also say that (1) is a Weierstrass model for C. L-Rational points For any field extension L=K we can consider the L-rational points on C, i.e. the points on C with coordinates in L: 2 C(L) := f(x : y : z) 2 PL : equation (1) is satisfied g: The point at infinity The point O := (0 : 1 : 0) 2 C(K) is the only K-rational point on C with z = 0. It is always smooth. Most of the time we shall instead of a homogeneous Weierstrass equation write an affine Weierstrass equation: 2 3 2 C : y + a1xy + a3y = x + a2x + a4x + a6 (2) which is understood to define a plane projective curve. The discriminant Define 2 b2 := a1 + 4a2; b4 := 2a4 + a1a3; 2 b6 := a3 + 4a6; 2 2 2 b8 := a1a6 + 4a2a6 − a1a3a4 + a2a3 − a4: For any Weierstrass equation we define its discriminant 2 3 2 ∆ := −b2b8 − 8b4 − 27b6 + 9b2b4b6: 1 Note that if char(K) 6= 2, then we can perform the coordinate transformation 2 3 2 y 7! (y − a1x − a3)=2 to arrive at an equation y = 4x + b2x + 2b4x + b6. -
The Klein Quartic in Number Theory
The Eightfold Way MSRI Publications Volume 35, 1998 The Klein Quartic in Number Theory NOAM D. ELKIES Abstract. We describe the Klein quartic X and highlight some of its re- markable properties that are of particular interest in number theory. These include extremal properties in characteristics 2, 3, and 7, the primes divid- ing the order of the automorphism group of X; an explicit identification of X with the modular curve X(7); and applications to the class number 1 problem and the case n = 7 of Fermat. Introduction Overview. In this expository paper we describe some of the remarkable prop- erties of the Klein quartic that are of particular interest in number theory. The Klein quartic X is the unique curve of genus 3 over C with an automorphism group G of size 168, the maximum for its genus. Since G is central to the story, we begin with a detailed description of G and its representation on the 2 three-dimensional space V in whose projectivization P(V )=P the Klein quar- tic lives. The first section is devoted to this representation and its invariants, starting over C and then considering arithmetical questions of fields of definition and integral structures. There we also encounter a G-lattice that later occurs as both the period lattice and a Mordell–Weil lattice for X. In the second section we introduce X and investigate it as a Riemann surface with automorphisms by G. In the third section we consider the arithmetic of X: rational points, relations with the Fermat curve and Fermat’s “Last Theorem” for exponent 7, and some extremal properties of the reduction of X modulo the primes 2, 3, 7 dividing #G. -
The Modularity Theorem
R. van Dobben de Bruyn The Modularity Theorem Bachelor's thesis, June 21, 2011 Supervisors: Dr R.M. van Luijk, Dr C. Salgado Mathematisch Instituut, Universiteit Leiden Contents Introduction4 1 Elliptic Curves6 1.1 Definitions and Examples......................6 1.2 Minimal Weierstrass Form...................... 11 1.3 Reduction Modulo Primes...................... 14 1.4 The Frey Curve and Fermat's Last Theorem............ 15 2 Modular Forms 18 2.1 Definitions............................... 18 2.2 Eisenstein Series and the Discriminant............... 21 2.3 The Ring of Modular Forms..................... 25 2.4 Congruence Subgroups........................ 28 3 The Modularity Theorem 36 3.1 Statement of the Theorem...................... 36 3.2 Fermat's Last Theorem....................... 36 References 39 2 Introduction One of the longest standing open problems in mathematics was Fermat's Last Theorem, asserting that the equation an + bn = cn does not have any nontrivial (i.e. with abc 6= 0) integral solutions when n is larger than 2. The proof, which was completed in 1995 by Wiles and Taylor, relied heavily on the Modularity Theorem, relating elliptic curves over Q to modular forms. The Modularity Theorem has many different forms, some of which are stated in an analytic way using Riemann surfaces, while others are stated in a more algebraic way, using for instance L-series or Galois representations. This text will present an elegant, elementary formulation of the theorem, using nothing more than some basic vocabulary of both elliptic curves and modular forms. For elliptic curves E over Q, we will examine the reduction E~ of E modulo any prime p, thus introducing the quantity ~ ap(E) = p + 1 − #E(Fp): We will also give an almost complete description of the conductor NE associated to an elliptic curve E, and compute it for the curve used in the proof of Fermat's Last Theorem. -
Explicit Towers of Drinfeld Modular Curves 3
Explicit towers of Drinfeld modular curves Noam D. Elkies Abstract. We give explicit equations for the simplest towers of Drinfeld modu- lar curves over any finite field, and observe that they coincide with the asymp- totically optimal towers of curves constructed by Garcia and Stichtenoth. 1. Introduction Fix a finite field k1 of size q1. It has been known for almost twenty years (see 1/2 [16, 18, 17]) that any curve C/k1 of genus g = g(C) has at most (q1 − 1+ o(1))g points rational over k1 as g → ∞ (the Drinfeld-Vl˘adut¸bound [1]), and that if q1 is a square then there are various families of classical, Shimura, or 1/2 Drinfeld modular curves C/k1 of genus g → ∞ with #(C(k1)) ≥ (q1 − 1)(g − 1). Thus such curves are “asymptotically optimal”: they attain the lim sup of #(C(k1))/g(C). Moreover, asymptotically optimal curves yield excellent linear error-correcting codes over k1 [12, 17]. To actually construct and use these Goppa codes one needs explicit equations for asymptotically optimal C. Now the definitions of modular curves are in principle constructive, but it is usually not feasible to actually exhibit a given modular curve. For certain Drinfeld modular curves, [17, pp.453ff.] gives explicit, albeit unpleasant, models as plane curves with two complicated singularities. Garcia and Stichtenoth gave nice formulas for asymptotically optimal families of curves in [6] for q1 = 4, 9 (see also [7]), and in [4] for all square prime powers q1. In each case they construct a sequence of curves C1, C2, C3,.. -
Dedekind $\Eta $-Function, Hauptmodul and Invariant Theory
Dedekind η-function, Hauptmodul and invariant theory Lei Yang Abstract We solve a long-standing open problem with its own long history dating back to the celebrated works of Klein and Ramanujan. This problem concerns the invariant decomposition formulas of the Hauptmodul for Γ0(p) under the action of finite simple groups PSL(2, p) with p =5, 7, 13. The cases of p = 5 and 7 were solved by Klein and Ramanujan. Little was known about this problem for p = 13. Using our invariant theory for PSL(2, 13), we solve this problem. This leads to a new expression of the classical elliptic modular function of Klein: j-function in terms of theta constants associated with Γ(13). Moreover, we find an exotic modular equation, i.e., it has the same form as Ramanujan’s modular equation of degree 13, but with different kinds of modular parametrizations, which gives the geometry of the classical modular curve X(13). Contents 1. Introduction 2. Six-dimensional representations of PSL(2, 13) and transformation formulas for theta constants 3. Seven-dimensional representations of PSL(2, 13), exotic modular equation and geometry of modular curve X(13) 4. Fourteen-dimensional representations of PSL(2, 13) and invariant decomposition formula arXiv:1407.3550v2 [math.NT] 18 Aug 2014 1. Introduction In many applications of elliptic modular functions to number theory the Dedekind eta function plays a central role. It is defined in the upper-half plane H = z C : Im(z) > 0 by { ∈ } ∞ 1 n 2πiz η(z) := q 24 (1 q ), q = e . -
On Quadratic Points of Classical Modular Curves
ON QUADRATIC POINTS OF CLASSICAL MODULAR CURVES FRANCESC BARS Dedicated to the memory of F. Momose Abstract. Classical modular curves are of deep interest in arithmetic geom- etry. In this survey we show how the work of Fumiyuki Momose is involved in order to list the classical modular curves which satisfy that the set of qua- dratic points over Q is in¯nite. In particular we recall results of Momose on hyperelliptic modular curves and on automorphisms groups of modular curves. Moreover, we ¯x some inaccuracies of the existing literature in few statements concerning automorphism groups of modular curves and we make available di®erent results that are di±cult to ¯nd a precise reference, for exam- ple: arithmetical results on hyperelliptic and bielliptic curves (like the arith- metical statement of the main theorem of Harris and Silverman in [12], or the case d = 2 of Abramovich and Harris theorem in [1]) and on the conductor of elliptic curves over Q parametrized by X(N). 1. Introduction The propose of this survey is to present the relation of the work of Professor Fumiyuki Momose with the determination of classical modular curves which have an in¯nite set of quadratic points over Q. Over the complex numbers, a classical modular curve X¡;C corresponds to a Riemann surface obtained by completing by the cusps the a±ne curve H=¡ where H is the upper half plane and ¡ is a modular subgroup of SL2(Z). For this survey let us consider the following modular subgroups ¡ of SL2(Z) with N a positive integer and ¢ a strict subgroup of (Z=NZ)¤ with ¡1 2 ¢: ½µ ¶ ¯µ ¶ µ ¶ ¾ a b ¯ a b 1 0 ¡(N) = 2 SL (Z) ¯ ´ (mod N) ; c d 2 ¯ c d 0 1 ½µ ¶ ¯µ ¶ µ ¶ ¾ a b ¯ a b 1 ¤ ¡ (N) = 2 SL (Z) ¯ ´ (mod N) ; 1 c d 2 ¯ c d 0 1 ½µ ¶ ¾ a b ¡ (N) = 2 ¡ (N) j (a (mod N)) 2 ¢ ; ¢ c d 0 ½µ ¶ ¯µ ¶ µ ¶ ¾ a b ¯ a b ¤ ¤ ¡ (N) = 2 SL (Z) ¯ ´ (mod N) : 0 c d 2 ¯ c d 0 ¤ Let us denote the associated Riemann surfaces (or complex modular curves as- sociated to the modular subgroups) by X(N)C;X1(N)C;X¢(N)C and X0(N)C re- spectively. -
Pre-Publication Accepted Manuscript
Yifan Yang Special values of hypergeometric functions and periods of CM elliptic curves Transactions of the American Mathematical Society DOI: 10.1090/tran/7134 Accepted Manuscript This is a preliminary PDF of the author-produced manuscript that has been peer-reviewed and accepted for publication. It has not been copyedited, proofread, or finalized by AMS Production staff. Once the accepted manuscript has been copyedited, proofread, and finalized by AMS Production staff, the article will be published in electronic form as a \Recently Published Article" before being placed in an issue. That electronically published article will become the Version of Record. This preliminary version is available to AMS members prior to publication of the Version of Record, and in limited cases it is also made accessible to everyone one year after the publication date of the Version of Record. The Version of Record is accessible to everyone five years after publication in an issue. This is a pre-publication version of this article, which may differ from the final published version. Copyright restrictions may apply. SPECIAL VALUES OF HYPERGEOMETRIC FUNCTIONS AND PERIODS OF CM ELLIPTIC CURVES YIFAN YANG 6 6 ABSTRACT. Let X0 (1)=W6 be the Atkin-Lehner quotient of the Shimura curve X0 (1) associated to a maximal order in an indefinite quaternion algebra of discriminant 6 over Q. 6 By realizing modular forms on X0 (1)=W6 in two ways, one in terms of hypergeometric functions and the other in terms of Borcherds forms, and using Schofer’s formula for val- ues of Borcherds forms at CM-points, we obtain special values of certain hypergeometric functions in terms of periods of elliptic curves over Q with complex multiplication. -
"Rank Zero Quadratic Twists of Modular Elliptic Curves" by Ken
RANK ZERO QUADRATIC TWISTS OF MODULAR ELLIPTIC CURVES Ken Ono Abstract. In [11] L. Mai and M. R. Murty proved that if E is a modular elliptic curve with conductor N, then there exists infinitely many square-free integers D ≡ 1 mod 4N such that ED, the D−quadratic twist of E, has rank 0. Moreover assuming the Birch and Swinnerton-Dyer Conjecture, they obtain analytic estimates on the lower bounds for the orders of their Tate-Shafarevich groups. However regarding ranks, simply by the sign of functional equations, it is not expected that there will be infinitely many square-free D in every arithmetic progression r (mod t) where gcd(r, t) is square-free such that ED has rank zero. Given a square-free positive integer r, under mild conditions we show that there ×2 exists an integer tr and a positive integer N where tr ≡ r mod Qp for all p | N, such that 0 there are infinitely many positive square-free integers D ≡ tr mod N where ED has rank 0 0 Q zero. The modulus N is defined by N := 8 p|N p where the product is over odd primes p dividing N. As an example of this theorem, let E be defined by y2 = x3 + 15x2 + 36x. If r = 1, 3, 5, 9, 11, 13, 17, 19, 21, then there exists infinitely many positive square-free in- tegers D ≡ r mod 24 such that ED has rank 0. As another example, let E be defined by y2 = x3 − 1. If r = 1, 2, 5, 10, 13, 14, 17, or 22, then there exists infinitely many positive square-free integers D ≡ r mod 24 such that ED has rank 0. -
Algebraic Cycles and Stark-Heegner Points
Algebraic cycles and Stark-Heegner points Henri Darmon Victor Rotger July 2, 2011 2 Contents 1 The conjecture of Birch and Swinnerton-Dyer 7 1.1 Prelude: units in number fields . 7 1.2 Rational points on elliptic curves . 10 2 Modular forms and analytic continuation 15 2.1 Quaternionic Shimura varieties . 15 2.2 Modular forms on quaternion algebras . 17 2.3 Modularity over totally real fields . 19 3 Heegner points 23 3.1 Definition and construction . 23 3.2 Numerical calculation . 27 4 Algebraic cycles and de Rham cohomology 33 4.1 Algebraic cycles . 33 4.2 de Rham cohomology . 35 4.3 Cycle classes and Abel-Jacobi maps . 40 5 Chow-Heegner points 43 5.1 Generalities . 43 5.2 Generalised Heegner cycles . 45 6 Motives and L-functions 51 6.1 Motives . 51 6.2 L-functions . 56 6.3 The Birch and Swinnerton-Dyer conjecture, revisited . 60 7 Triple product of Kuga-Sato varieties 65 7.1 Diagonal cycles . 65 7.2 Triple Chow-Heegner points . 68 8 p-adic L-functions 71 8.1 p-adic families of motives . 71 3 4 CONTENTS 8.2 p-adic L-functions . 76 9 Two p-adic Gross-Zagier formulae 83 10 Stark-Heegner points and Artin representations 87 Introduction Stark-Heegner points are canonical global points on elliptic curves or modular abelian vari- eties which admit{often conjecturally{explicit analytic constructions as well as direct rela- tions to L-series, both complex and p-adic. The ultimate aim of these notes is to present a new approach to this theory based on algebraic cycles, Rankin triple product L-functions, and p-adic families of modular forms.