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Small discriminants of complex multiplication fields of elliptic curves over finite fields

Igor E. Shparlinski (2015)

Czechoslovak Mathematical Journal

We obtain a conditional, under the Generalized Riemann Hypothesis, lower bound on the number of distinct elliptic curves E over a prime finite field 𝔽 p of p elements, such that the discriminant D ( E ) of the quadratic number field containing the endomorphism ring of E over 𝔽 p is small. For almost all primes we also obtain a similar unconditional bound. These lower bounds complement an upper bound of F. Luca and I. E. Shparlinski (2007).

Small exponent point groups on elliptic curves

Florian Luca, James McKee, Igor E. Shparlinski (2006)

Journal de Théorie des Nombres de Bordeaux

Let E be an elliptic curve defined over F q , the finite field of q elements. We show that for some constant η > 0 depending only on q , there are infinitely many positive integers n such that the exponent of E ( F q n ) , the group of F q n -rational points on E , is at most q n exp - n η / log log n . This is an analogue of a result of R. Schoof on the exponent of the group E ( F p ) of F p -rational points, when a fixed elliptic curve E is defined over and the prime p tends to infinity.

Small generators of function fields

Martin Widmer (2010)

Journal de Théorie des Nombres de Bordeaux

Let 𝕂 / k be a finite extension of a global field. Such an extension can be generated over k by a single element. The aim of this article is to prove the existence of a ”small” generator in the function field case. This answers the function field version of a question of Ruppert on small generators of number fields.

Small points on a multiplicative group and class number problem

Francesco Amoroso (2007)

Journal de Théorie des Nombres de Bordeaux

Let V be an algebraic subvariety of a torus 𝔾 m n n and denote by V * the complement in V of the Zariski closure of the set of torsion points of V . By a theorem of Zhang, V * is discrete for the metric induced by the normalized height h ^ . We describe some quantitative versions of this result, close to the conjectural bounds, and we discuss some applications to study of the class group of some number fields.

Solutions of cubic equations in quadratic fields

K. Chakraborty, Manisha V. Kulkarni (1999)

Acta Arithmetica

Let K be any quadratic field with K its ring of integers. We study the solutions of cubic equations, which represent elliptic curves defined over ℚ, in quadratic fields and prove some interesting results regarding the solutions by using elementary tools. As an application we consider the Diophantine equation r+s+t = rst = 1 in K . This Diophantine equation gives an elliptic curve defined over ℚ with finite Mordell-Weil group. Using our study of the solutions of cubic equations in quadratic fields...

Solving an indeterminate third degree equation in rational numbers. Sylvester and Lucas

Tatiana Lavrinenko (2002)

Revue d'histoire des mathématiques

This article concerns the problem of solving diophantine equations in rational numbers. It traces the way in which the 19th century broke from the centuries-old tradition of the purely algebraic treatment of this problem. Special attention is paid to Sylvester’s work “On Certain Ternary Cubic-Form Equations” (1879–1880), in which the algebraico-geometrical approach was applied to the study of an indeterminate equation of third degree.

Some examples of 5 and 7 descent for elliptic curves over Q

Tom Fisher (2001)

Journal of the European Mathematical Society

We perform descent calculations for the families of elliptic curves over Q with a rational point of order n = 5 or 7. These calculations give an estimate for the Mordell-Weil rank which we relate to the parity conjecture. We exhibit explicit elements of the Tate-Shafarevich group of order 5 and 7, and show that the 5-torsion of the Tate-Shafarevich group of an elliptic curve over Q may become arbitrarily large.

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