RAMANUJAN INVARIANTS FOR DISCRIMINANTS CONGRUENT TO 5 (mod 24)

2012 ◽  
Vol 08 (01) ◽  
pp. 265-287 ◽  
Author(s):  
ELISAVET KONSTANTINOU ◽  
ARISTIDES KONTOGEORGIS
Keyword(s):  
Number Theory ◽  
Computer Science ◽  
Modular Functions ◽  
Minimal Polynomials ◽  
Reciprocity Law ◽  
Class Invariants ◽  
Lecture Notes ◽  
Yield Class ◽  
Class Fields

In this paper we compute the minimal polynomials of Ramanujan values [Formula: see text] for discriminants D ≡ 5 ( mod 24). Our method is based on Shimura Reciprocity Law as which was made computationally explicit by Gee and Stevenhagen in [Generating class fields using Shimura reciprocity, in Algorithmic Number Theory, Lecture Notes in Computer Science, Vol. 1423 (Springer, Berlin, 1998), pp. 441–453; MR MR1726092 (2000m:11112)]. However, since these Ramanujan values are not class invariants, we present a modification of the method used in [Generating class fields using Shimura reciprocity, in Algorithmic Number Theory, Lecture Notes in Computer Science, Vol. 1423 (Springer, Berlin, 1998), pp. 441–453; MR MR1726092 (2000m:11112)] which can be applied on modular functions that do not necessarily yield class invariants.

scholarly journals Singular values of multiple eta-quotients for ramified primes

2013 ◽  
Vol 16 ◽  
pp. 407-418 ◽  
Author(s):  
Andreas Enge ◽  
Reinhard Schertz
Keyword(s):  
Complex Multiplication ◽  
Singular Values ◽  
Number Fields ◽  
Algebraic Numbers ◽  
Modular Functions ◽  
Class Invariants ◽  
Free Level ◽  
Yield Class ◽  
Imaginary Quadratic Number ◽  
Class Fields

AbstractWe determine the conditions under which singular values of multiple $\eta $-quotients of square-free level, not necessarily prime to six, yield class invariants; that is, algebraic numbers in ring class fields of imaginary-quadratic number fields. We show that the singular values lie in subfields of the ring class fields of index ${2}^{{k}^{\prime } - 1} $ when ${k}^{\prime } \geq 2$ primes dividing the level are ramified in the imaginary-quadratic field, which leads to faster computations of elliptic curves with prescribed complex multiplication. The result is generalised to singular values of modular functions on ${ X}_{0}^{+ } (p)$ for $p$ prime and ramified.

scholarly journals Coleman integration for even-degree models of hyperelliptic curves

2015 ◽  
Vol 18 (1) ◽  
pp. 258-265 ◽  
Author(s):  
Jennifer S. Balakrishnan
Keyword(s):  
Number Theory ◽  
Computer Science ◽  
Hyperelliptic Curves ◽  
Open Book ◽  
Line Integral ◽  
Book Series ◽  
Numerical Examples ◽  
Lecture Notes ◽  
Integration Algorithms ◽  
Mathematical Sciences

The Coleman integral is a $p$-adic line integral that encapsulates various quantities of number theoretic interest. Building on the work of Harrison [J. Symbolic Comput. 47 (2012) no. 1, 89–101], we extend the Coleman integration algorithms in Balakrishnan et al. [Algorithmic number theory, Lecture Notes in Computer Science 6197 (Springer, 2010) 16–31] and Balakrishnan [ANTS-X: Proceedings of the Tenth Algorithmic Number Theory Symposium, Open Book Series 1 (Mathematical Sciences Publishers, 2013) 41–61] to even-degree models of hyperelliptic curves. We illustrate our methods with numerical examples computed in Sage.

Computing Polynomials of the Ramanujan tn Class Invariants

2009 ◽  
Vol 52 (4) ◽  
pp. 583-597 ◽  
Author(s):  
Elisavet Konstantinou ◽  
Aristides Kontogeorgis
Keyword(s):  
Quadratic Field ◽  
Imaginary Quadratic Field ◽  
Class Field ◽  
Minimal Polynomials ◽  
Hilbert Polynomials ◽  
Reciprocity Law ◽  
Class Invariants ◽  
Hilbert Class Field

AbstractWe compute the minimal polynomials of the Ramanujan values tn, where n ≡ 11 mod 24, using the Shimura reciprocity law. These polynomials can be used for defining the Hilbert class field of the imaginary quadratic field and have much smaller coefficients than the Hilbert polynomials.

Construction of ray-class fields by smaller generators and their applications

2017 ◽  
Vol 147 (4) ◽  
pp. 781-812 ◽  
Author(s):  
Ja Kyung Koo ◽  
Dong Sung Yoon
Keyword(s):  
Diophantine Equations ◽  
Quadratic Fields ◽  
Imaginary Quadratic Fields ◽  
Minimal Polynomials ◽  
Class Invariants ◽  
Class Fields ◽  
Ray Class Fields

We generate ray-class fields over imaginary quadratic fields in terms of Siegel–Ramachandra invariants, which are an extension of a result of Schertz. By making use of quotients of Siegel–Ramachandra invariants we also construct ray-class invariants over imaginary quadratic fields whose minimal polynomials have relatively small coefficients, from which we are able to solve certain quadratic Diophantine equations.

scholarly journals Siegel families with application to class fields

2018 ◽  
Vol 148 (4) ◽  
pp. 751-771 ◽  
Author(s):  
Ja Kyung Koo ◽  
Dong Hwa Shin ◽  
Dong Sung Yoon
Keyword(s):  
Galois Groups ◽  
Algebraic Numbers ◽  
Modular Functions ◽  
Special Values ◽  
Reciprocity Law ◽  
Class Fields ◽  
Ray Class Fields ◽  
Natural Way

We investigate certain families of meromorphic Siegel modular functions on which Galois groups act in a natural way. By using Shimura's reciprocity law we construct some algebraic numbers in the ray class fields of CM-fields in terms of special values of functions in these Siegel families.

scholarly journals On some automorphic properties of Galois traces of class invariants from generalized Weber functions of level 5

2019 ◽  
Vol 17 (1) ◽  
pp. 1631-1651
Author(s):  
Ick Sun Eum ◽  
Ho Yun Jung
Keyword(s):  
Modular Forms ◽  
Fourier Coefficients ◽  
Singular Values ◽  
Congruence Subgroups ◽  
Maass Form ◽  
Weakly Holomorphic Modular Forms ◽  
Reciprocity Law ◽  
Class Invariants ◽  
Higher Genus ◽  
Holomorphic Modular Forms

Abstract After the significant work of Zagier on the traces of singular moduli, Jeon, Kang and Kim showed that the Galois traces of real-valued class invariants given in terms of the singular values of the classical Weber functions can be identified with the Fourier coefficients of weakly holomorphic modular forms of weight 3/2 on the congruence subgroups of higher genus by using the Bruinier-Funke modular traces. Extending their work, we construct real-valued class invariants by using the singular values of the generalized Weber functions of level 5 and prove that their Galois traces are Fourier coefficients of a harmonic weak Maass form of weight 3/2 by using Shimura’s reciprocity law.

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