A parametric family of quartic Thue inequalities

Let c\neq 0,-1 be an integer. In this paper, we use the method of Tzanakis to transform the quartic Thue equation x^4 -(c^2+c+4) x^3y +(c^2+c+3) x^2 y^2 +2 xy^3 -y^4 = \mu into systems of Pell equations. Then, we determine all primitive solutions (x,y) with 0<|\mu|\leq |c+1|.

Thue's equation as a tool to solve two different problems

A Thue equation is a Diophantine equation of the form f(x; y) = r, where f is an irreducible binary form of degree at least 3, and r is a given nonzero rational number. A set S of at least three positive integers is called a D13-set if the product of any of its three distinct elements is a perfect cube minus one. We prove that any D13-set is finite and, for any positive integer a, the two-tuple {a, 2a} is extendible to a D13-set 3-tuple, but not to a 4-tuple. Using the well-known Thue equation 2x3 - y3 = 1, we show that the only cubic-triangular number is 1.

On cubic Thue equations and the indices of algebraic integers in cubic fields

Let F(x; y) = ax3 + bx2y + cxy2 + dy3 ? Z[x,y] be an irreducible cubic form. In this paper, we investigate arithmetic properties of the common indices of algebraic integers in cubic fields. For each integer k such that v2(k)??0 (mod 3) and 2v2(-2b3 - 27a2d + 9abc) = 3v2(b2 - 3ac), we prove that the cubic Thue equation F(x,y) = k has no solution (x,y) ? Z2. As application, we construct parametrized families of twisted elliptic curves E : ax3 + bx2 + cx + d = ey2 without integer points (x,y).

On equation Xn − 1 = BZn

We consider the Diophantine equation [Formula: see text], where [Formula: see text] is understood as a parameter. We prove that if the equation has a solution, then either the Euler totient of the radical, [Formula: see text], has a common divisor with the exponent [Formula: see text], or the exponent is a prime and the solution stems from a solution to the diagonal case of the Nagell–Ljunggren equation: [Formula: see text]. This allows us to apply recent results on this equation to the binary Thue equation in question. In particular, we can then display parametrized families for which the Thue equation has no solution. The first such family was proved by Bennett in his seminal paper on binary Thue equations (see [M. A. Bennet, Rational approximation to algebraic numbers of small height: the Diophantine equation [Formula: see text], J. Reine Angew. Math. 535 (2001) 1–49]).

Calculating Power Integral bases by Solving Relative Thue Equations

In our recent paper I. Gaál: Calculating “small” solutions of relative Thue equations, J. Experiment. Math. (to appear) we gave an efficient algorithm to calculate “small” solutions of relative Thue equations (where “small” means an upper bound of type 10500 for the sizes of solutions). Here we apply this algorithm to calculating power integral bases in sextic fields with an imaginary quadratic subfield and to calculating relative power integral bases in pure quartic extensions of imaginary quadratic fields. In both cases the crucial point of the calculation is the resolution of a relative Thue equation. We produce numerical data that were not known before.

NUMBER OF SOLUTIONS FOR QUARTIC SIMPLE THUE EQUATIONS

Let F(X, Y) = bX4 - aX3Y - 6bX2Y2 + aXY3 + bY4 ∈ Z[X, Y]. We show that the number of solutions for the Thue equation F(x, y) = ±1 is 0 or 4 except for a few already known cases. To obtain an upper bound for the size of solutions, we use Padé approximation method. To obtain a lower bound for the size of solutions, we construct a continued fraction with positive or negative rational partial quotients. This construction is carried out carefully by using special properties of the form F. Combining these lower and upper bounds, we obtain the result.

A SYSTEM OF RELATIVE PELLIAN EQUATIONS AND A RELATED FAMILY OF RELATIVE THUE EQUATIONS

In this paper we consider the family of systems (2c + 1)U2 - 2cV2 = μ and (c - 2)U2 - cZ2 = -2μ of relative Pellian equations, where the parameter c and the root of unity μ are integers in the same imaginary quadratic number field [Formula: see text]. We show that for |c| ≥ 3 only certain values of μ yield solutions of this system, and solve the system completely for |c| ≥ 1544686. Furthermore we will consider the related relative Thue equation [Formula: see text] and solve it by the method of Tzanakis under the same assumptions.