25 Modular Forms and L-Functions
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The Class Number One Problem for Imaginary Quadratic Fields
MODULAR CURVES AND THE CLASS NUMBER ONE PROBLEM JEREMY BOOHER Gauss found 9 imaginary quadratic fields with class number one, and in the early 19th century conjectured he had found all of them. It turns out he was correct, but it took until the mid 20th century to prove this. Theorem 1. Let K be an imaginary quadratic field whose ring of integers has class number one. Then K is one of p p p p p p p p Q(i); Q( −2); Q( −3); Q( −7); Q( −11); Q( −19); Q( −43); Q( −67); Q( −163): There are several approaches. Heegner [9] gave a proof in 1952 using the theory of modular functions and complex multiplication. It was dismissed since there were gaps in Heegner's paper and the work of Weber [18] on which it was based. In 1967 Stark gave a correct proof [16], and then noticed that Heegner's proof was essentially correct and in fact equiv- alent to his own. Also in 1967, Baker gave a proof using lower bounds for linear forms in logarithms [1]. Later, Serre [14] gave a new approach based on modular curve, reducing the class number + one problem to finding special points on the modular curve Xns(n). For certain values of n, it is feasible to find all of these points. He remarks that when \N = 24 An elliptic curve is obtained. This is the level considered in effect by Heegner." Serre says nothing more, and later writers only repeat this comment. This essay will present Heegner's argument, as modernized in Cox [7], then explain Serre's strategy. -
Euler Product Asymptotics on Dirichlet L-Functions 3
EULER PRODUCT ASYMPTOTICS ON DIRICHLET L-FUNCTIONS IKUYA KANEKO Abstract. We derive the asymptotic behaviour of partial Euler products for Dirichlet L-functions L(s,χ) in the critical strip upon assuming only the Generalised Riemann Hypothesis (GRH). Capturing the behaviour of the partial Euler products on the critical line is called the Deep Riemann Hypothesis (DRH) on the ground of its importance. Our result manifests the positional relation of the GRH and DRH. If χ is a non-principal character, we observe the √2 phenomenon, which asserts that the extra factor √2 emerges in the Euler product asymptotics on the central point s = 1/2. We also establish the connection between the behaviour of the partial Euler products and the size of the remainder term in the prime number theorem for arithmetic progressions. Contents 1. Introduction 1 2. Prelude to the asymptotics 5 3. Partial Euler products for Dirichlet L-functions 6 4. Logarithmical approach to Euler products 7 5. Observing the size of E(x; q,a) 8 6. Appendix 9 Acknowledgement 11 References 12 1. Introduction This paper was motivated by the beautiful and profound work of Ramanujan on asymptotics for the partial Euler product of the classical Riemann zeta function ζ(s). We handle the family of Dirichlet L-functions ∞ L(s,χ)= χ(n)n−s = (1 χ(p)p−s)−1 with s> 1, − ℜ 1 p X Y arXiv:1902.04203v1 [math.NT] 12 Feb 2019 and prove the asymptotic behaviour of partial Euler products (1.1) (1 χ(p)p−s)−1 − 6 pYx in the critical strip 0 < s < 1, assuming the Generalised Riemann Hypothesis (GRH) for this family. -
Arxiv:2003.01675V1 [Math.NT] 3 Mar 2020 of Their Locations
DIVISORS OF MODULAR PARAMETRIZATIONS OF ELLIPTIC CURVES MICHAEL GRIFFIN AND JONATHAN HALES Abstract. The modularity theorem implies that for every elliptic curve E=Q there exist rational maps from the modular curve X0(N) to E, where N is the conductor of E. These maps may be expressed in terms of pairs of modular functions X(z) and Y (z) where X(z) and Y (z) satisfy the Weierstrass equation for E as well as a certain differential equation. Using these two relations, a recursive algorithm can be used to calculate the q - expansions of these parametrizations at any cusp. Using these functions, we determine the divisor of the parametrization and the preimage of rational points on E. We give a sufficient condition for when these preimages correspond to CM points on X0(N). We also examine a connection between the al- gebras generated by these functions for related elliptic curves, and describe sufficient conditions to determine congruences in the q-expansions of these objects. 1. Introduction and statement of results The modularity theorem [2, 12] guarantees that for every elliptic curve E of con- ductor N there exists a weight 2 newform fE of level N with Fourier coefficients in Z. The Eichler integral of fE (see (3)) and the Weierstrass }-function together give a rational map from the modular curve X0(N) to the coordinates of some model of E: This parametrization has singularities wherever the value of the Eichler integral is in the period lattice. Kodgis [6] showed computationally that many of the zeros of the Eichler integral occur at CM points. -
Dessins D'enfants in N = 2 Generalised Quiver Theories Arxiv
Dessins d'Enfants in N = 2 Generalised Quiver Theories Yang-Hui He1 and James Read2 1Department of Mathematics, City University, London, Northampton Square, London EC1V 0HB, UK; School of Physics, NanKai University, Tianjin, 300071, P.R. China; Merton College, University of Oxford, OX1 4JD, UK [email protected] 2Merton College, University of Oxford, OX1 4JD, UK [email protected] Abstract We study Grothendieck's dessins d'enfants in the context of the N = 2 super- symmetric gauge theories in (3 + 1) dimensions with product SU (2) gauge groups arXiv:1503.06418v2 [hep-th] 15 Sep 2015 which have recently been considered by Gaiotto et al. We identify the precise con- text in which dessins arise in these theories: they are the so-called ribbon graphs of such theories at certain isolated points in the moduli space. With this point in mind, we highlight connections to other work on trivalent dessins, gauge theories, and the modular group. 1 Contents 1 Introduction3 2 Dramatis Personæ6 2.1 Skeleton Diagrams . .6 2.2 Moduli Spaces . .8 2.3 BPS Quivers . .9 2.4 Quadratic Differentials and Graphs on Gaiotto Curves . 11 2.5 Dessins d'Enfants and Belyi Maps . 12 2.6 The Modular Group and Congruence Subgroups . 14 3 A Web of Correspondences 15 3.1 Quadratic Differentials and Seiberg-Witten Curves . 16 3.2 Trajectories on Riemann Surfaces and Ideal Triangulations . 16 3.3 Constructing BPS Quivers . 20 3.4 Skeleton Diagrams and BPS Quivers . 21 3.5 Strebel Differentials and Ribbon Graphs . 23 3.5.1 Ribbon Graphs from Strebel Differentials . -
Generalization of a Theorem of Hurwitz
J. Ramanujan Math. Soc. 31, No.3 (2016) 215–226 Generalization of a theorem of Hurwitz Jung-Jo Lee1,∗ ,M.RamMurty2,† and Donghoon Park3,‡ 1Department of Mathematics, Kyungpook National University, Daegu 702-701, South Korea e-mail: [email protected] 2Department of Mathematics and Statistics, Queen’s University, Kingston, Ontario, K7L 3N6, Canada e-mail: [email protected] 3Department of Mathematics, Yonsei University, 50 Yonsei-Ro, Seodaemun-Gu, Seoul 120-749, South Korea e-mail: [email protected] Communicated by: R. Sujatha Received: February 10, 2015 Abstract. This paper is an exposition of several classical results formulated and unified using more modern terminology. We generalize a classical theorem of Hurwitz and prove the following: let 1 G (z) = k (mz + n)k m,n be the Eisenstein series of weight k attached to the full modular group. Let z be a CM point in the upper half-plane. Then there is a transcendental number z such that ( ) = 2k · ( ). G2k z z an algebraic number Moreover, z can be viewed as a fundamental period of a CM elliptic curve defined over the field of algebraic numbers. More generally, given any modular form f of weight k for the full modular group, and with ( )π k /k algebraic Fourier coefficients, we prove that f z z is algebraic for any CM point z lying in the upper half-plane. We also prove that for any σ Q Q ( ( )π k /k)σ = σ ( )π k /k automorphism of Gal( / ), f z z f z z . 2010 Mathematics Subject Classification: 11J81, 11G15, 11R42. -
Examples from Complex Geometry
Examples from Complex Geometry Sam Auyeung November 22, 2019 1 Complex Analysis Example 1.1. Two Heuristic \Proofs" of the Fundamental Theorem of Algebra: Let p(z) be a polynomial of degree n > 0; we can even assume it is a monomial. We also know that the number of zeros is at most n. We show that there are exactly n. 1. Proof 1: Recall that polynomials are entire functions and that Liouville's Theorem says that a bounded entire function is in fact constant. Suppose that p has no roots. Then 1=p is an entire function and it is bounded. Thus, it is constant which means p is a constant polynomial and has degree 0. This contradicts the fact that p has positive degree. Thus, p must have a root α1. We can then factor out (z − α1) from p(z) = (z − α1)q(z) where q(z) is an (n − 1)-degree polynomial. We may repeat the above process until we have a full factorization of p. 2. Proof 2: On the real line, an algorithm for finding a root of a continuous function is to look for when the function changes signs. How do we generalize this to C? Instead of having two directions, we have a whole S1 worth of directions. If we use colors to depict direction and brightness to depict magnitude, we can plot a graph of a continuous function f : C ! C. Near a zero, we'll see all colors represented. If we travel in a loop around any point, we can keep track of whether it passes through all the colors; around a zero, we'll pass through all the colors, possibly many times. -
Of the Riemann Hypothesis
A Simple Counterexample to Havil's \Reformulation" of the Riemann Hypothesis Jonathan Sondow 209 West 97th Street New York, NY 10025 [email protected] The Riemann Hypothesis (RH) is \the greatest mystery in mathematics" [3]. It is a conjecture about the Riemann zeta function. The zeta function allows us to pass from knowledge of the integers to knowledge of the primes. In his book Gamma: Exploring Euler's Constant [4, p. 207], Julian Havil claims that the following is \a tantalizingly simple reformulation of the Rie- mann Hypothesis." Havil's Conjecture. If 1 1 X (−1)n X (−1)n cos(b ln n) = 0 and sin(b ln n) = 0 na na n=1 n=1 for some pair of real numbers a and b, then a = 1=2. In this note, we first state the RH and explain its connection with Havil's Conjecture. Then we show that the pair of real numbers a = 1 and b = 2π=ln 2 is a counterexample to Havil's Conjecture, but not to the RH. Finally, we prove that Havil's Conjecture becomes a true reformulation of the RH if his conclusion \then a = 1=2" is weakened to \then a = 1=2 or a = 1." The Riemann Hypothesis In 1859 Riemann published a short paper On the number of primes less than a given quantity [6], his only one on number theory. Writing s for a complex variable, he assumes initially that its real 1 part <(s) is greater than 1, and he begins with Euler's product-sum formula 1 Y 1 X 1 = (<(s) > 1): 1 ns p 1 − n=1 ps Here the product is over all primes p. -
Supersingular Zeros of Divisor Polynomials of Elliptic Curves of Prime Conductor
Kazalicki and Kohen Res Math Sci(2017) 4:10 DOI 10.1186/s40687-017-0099-8 R E S E A R C H Open Access Supersingular zeros of divisor polynomials of elliptic curves of prime conductor Matija Kazalicki1* and Daniel Kohen2,3 *Correspondence: [email protected] Abstract 1Department of Mathematics, p p University of Zagreb, Bijeniˇcka For a prime number , we study the zeros modulo of divisor polynomials of rational cesta 30, 10000 Zagreb, Croatia elliptic curves E of conductor p. Ono (CBMS regional conference series in mathematics, Full list of author information is 2003, vol 102, p. 118) made the observation that these zeros are often j-invariants of available at the end of the article supersingular elliptic curves over Fp. We show that these supersingular zeros are in bijection with zeros modulo p of an associated quaternionic modular form vE .This allows us to prove that if the root number of E is −1 then all supersingular j-invariants of elliptic curves defined over Fp are zeros of the corresponding divisor polynomial. If the root number is 1, we study the discrepancy between rank 0 and higher rank elliptic curves, as in the latter case the amount of supersingular zeros in Fp seems to be larger. In order to partially explain this phenomenon, we conjecture that when E has positive rank the values of the coefficients of vE corresponding to supersingular elliptic curves defined over Fp are even. We prove this conjecture in the case when the discriminant of E is positive, and obtain several other results that are of independent interest. -
A Glimpse of the Laureate's Work
A glimpse of the Laureate’s work Alex Bellos Fermat’s Last Theorem – the problem that captured planets moved along their elliptical paths. By the beginning Andrew Wiles’ imagination as a boy, and that he proved of the nineteenth century, however, they were of interest three decades later – states that: for their own properties, and the subject of work by Niels Henrik Abel among others. There are no whole number solutions to the Modular forms are a much more abstract kind of equation xn + yn = zn when n is greater than 2. mathematical object. They are a certain type of mapping on a certain type of graph that exhibit an extremely high The theorem got its name because the French amateur number of symmetries. mathematician Pierre de Fermat wrote these words in Elliptic curves and modular forms had no apparent the margin of a book around 1637, together with the connection with each other. They were different fields, words: “I have a truly marvelous demonstration of this arising from different questions, studied by different people proposition which this margin is too narrow to contain.” who used different terminology and techniques. Yet in the The tantalizing suggestion of a proof was fantastic bait to 1950s two Japanese mathematicians, Yutaka Taniyama the many generations of mathematicians who tried and and Goro Shimura, had an idea that seemed to come out failed to find one. By the time Wiles was a boy Fermat’s of the blue: that on a deep level the fields were equivalent. Last Theorem had become the most famous unsolved The Japanese suggested that every elliptic curve could be problem in mathematics, and proving it was considered, associated with its own modular form, a claim known as by consensus, well beyond the reaches of available the Taniyama-Shimura conjecture, a surprising and radical conceptual tools. -
A Review on Elliptic Curve Cryptography for Embedded Systems
International Journal of Computer Science & Information Technology (IJCSIT), Vol 3, No 3, June 2011 A REVIEW ON ELLIPTIC CURVE CRYPTOGRAPHY FOR EMBEDDED SYSTEMS Rahat Afreen 1 and S.C. Mehrotra 2 1Tom Patrick Institute of Computer & I.T, Dr. Rafiq Zakaria Campus, Rauza Bagh, Aurangabad. (Maharashtra) INDIA [email protected] 2Department of C.S. & I.T., Dr. B.A.M. University, Aurangabad. (Maharashtra) INDIA [email protected] ABSTRACT Importance of Elliptic Curves in Cryptography was independently proposed by Neal Koblitz and Victor Miller in 1985.Since then, Elliptic curve cryptography or ECC has evolved as a vast field for public key cryptography (PKC) systems. In PKC system, we use separate keys to encode and decode the data. Since one of the keys is distributed publicly in PKC systems, the strength of security depends on large key size. The mathematical problems of prime factorization and discrete logarithm are previously used in PKC systems. ECC has proved to provide same level of security with relatively small key sizes. The research in the field of ECC is mostly focused on its implementation on application specific systems. Such systems have restricted resources like storage, processing speed and domain specific CPU architecture. KEYWORDS Elliptic curve cryptography Public Key Cryptography, embedded systems, Elliptic Curve Digital Signature Algorithm ( ECDSA), Elliptic Curve Diffie Hellman Key Exchange (ECDH) 1. INTRODUCTION The changing global scenario shows an elegant merging of computing and communication in such a way that computers with wired communication are being rapidly replaced to smaller handheld embedded computers using wireless communication in almost every field. This has increased data privacy and security requirements. -
Contents 5 Elliptic Curves in Cryptography
Cryptography (part 5): Elliptic Curves in Cryptography (by Evan Dummit, 2016, v. 1.00) Contents 5 Elliptic Curves in Cryptography 1 5.1 Elliptic Curves and the Addition Law . 1 5.1.1 Cubic Curves, Weierstrass Form, Singular and Nonsingular Curves . 1 5.1.2 The Addition Law . 3 5.1.3 Elliptic Curves Modulo p, Orders of Points . 7 5.2 Factorization with Elliptic Curves . 10 5.3 Elliptic Curve Cryptography . 14 5.3.1 Encoding Plaintexts on Elliptic Curves, Quadratic Residues . 14 5.3.2 Public-Key Encryption with Elliptic Curves . 17 5.3.3 Key Exchange and Digital Signatures with Elliptic Curves . 20 5 Elliptic Curves in Cryptography In this chapter, we will introduce elliptic curves and describe how they are used in cryptography. Elliptic curves have a long and interesting history and arise in a wide range of contexts in mathematics. The study of elliptic curves involves elements from most of the major disciplines of mathematics: algebra, geometry, analysis, number theory, topology, and even logic. Elliptic curves appear in the proofs of many deep results in mathematics: for example, they are a central ingredient in the proof of Fermat's Last Theorem, which states that there are no positive integer solutions to the equation xn + yn = zn for any integer n ≥ 3. Our goals are fairly modest in comparison, so we will begin by outlining the basic algebraic and geometric properties of elliptic curves and motivate the addition law. We will then study the behavior of elliptic curves modulo p: ultimately, there is a fairly strong analogy between the structure of the points on an elliptic curve modulo p and the integers modulo n. -
An Efficient Approach to Point-Counting on Elliptic Curves
mathematics Article An Efficient Approach to Point-Counting on Elliptic Curves from a Prominent Family over the Prime Field Fp Yuri Borissov * and Miroslav Markov Department of Mathematical Foundations of Informatics, Institute of Mathematics and Informatics, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria; [email protected] * Correspondence: [email protected] Abstract: Here, we elaborate an approach for determining the number of points on elliptic curves 2 3 from the family Ep = fEa : y = x + a (mod p), a 6= 0g, where p is a prime number >3. The essence of this approach consists in combining the well-known Hasse bound with an explicit formula for the quantities of interest-reduced modulo p. It allows to advance an efficient technique to compute the 2 six cardinalities associated with the family Ep, for p ≡ 1 (mod 3), whose complexity is O˜ (log p), thus improving the best-known algorithmic solution with almost an order of magnitude. Keywords: elliptic curve over Fp; Hasse bound; high-order residue modulo prime 1. Introduction The elliptic curves over finite fields play an important role in modern cryptography. We refer to [1] for an introduction concerning their cryptographic significance (see, as well, Citation: Borissov, Y.; Markov, M. An the pioneering works of V. Miller and N. Koblitz from 1980’s [2,3]). Briefly speaking, the Efficient Approach to Point-Counting advantage of the so-called elliptic curve cryptography (ECC) over the non-ECC is that it on Elliptic Curves from a Prominent requires smaller keys to provide the same level of security. Family over the Prime Field Fp.