Abstract. We will give upper bounds for the number of integral solutions to quartic Thue equations. Our main tool here is a logarithmic curve φ(x, y) that allows us to use the theory of linear forms in logarithms. This manuscript improves the results of author's earlier work with Okazaki [2] by giving special treatments to forms with respect to their signature.
IntroductionIn this paper, we will study binary quartic forms with integer coefficients; i.e. polynomials of the shapewith a i ∈ Z, i ∈ {0, 1, 2, 3, 4}. We aim to give upper bounds for the number of solutions to the equationHere we will count (x, y) and (−x, −y) as one solution. Let M (F ) be the Mahler measure of F (x, y). In [2] we used some ideas of Stewart [16] to bound the number of solutions with |y| < M (F ) 6 . We will slightly modify those ideas and use them to give an upper bound for the solutions of (1) with |y| < M (F ) 3.5 . Then we will improve the main result in [2] by giving better upper bounds for the number of solutions (x, y) with large |y| ≥ M (F ) 3.5 to equation (1). The following is the main result of this manuscript. Theorem 1.1. Let F (x, y) be an irreducible quartic binary form with integer coefficients. The Diophantine equation (1) has at most U F (see the table below) solutions in integers x and y, provided that the discriminant of F is greater than D 0 , where D 0 is an explicitly computable constant.The reason for having different upper bounds for forms with different signature in Theorem 1.1, relies upon the fact that the number fields generated over Q by a root of the equation F (x, 1) = 0 have a rings integers with different numbers of fundamental units.2010 Mathematics Subject Classification. 11J86, 11D45.