Finiteness criteria for the solutions of the sequence of semi-decomposable form equations and inequalities
Si Duc Quang
TL;DR
This work addresses finiteness criteria for solutions to sequences of semi-decomposable forms over a number field, focusing on $S$-integer solutions and $S$-unit proportionality. It develops a Schmidt-type inequality for families of homogeneous polynomials with distributive constant $\Delta$, bounding sums of Weil functions by $(\Delta(\tfrac{m}{2}+1)^2+\varepsilon)h(x)$ and enabling finiteness results when the semi-decomposable degree $\ell$ satisfies $\ell> d\Delta(\tfrac{m}{2}+1)^2$. The main result proves that, under these conditions and for $\lambda<\ell-d\Delta(\tfrac{m}{2}+1)^2$, there are no infinite sequences of $\mathcal{O}_S^*$-non-proportional $x_n$ with $0<\prod_{v\in S}\|F_n(x_n)\|_v\le c\,H_S^{\lambda}(x_n)$ and $h(F_n)=o(h(x_n))$, and provides a corollary for fixed $F$ with $\deg F> d\Delta(\tfrac{m}{2}+1)^2$ having only finitely many such solutions. These results generalize and unify prior finiteness theorems (e.g., Györy–Ru, Ji–Yan–Yu) via the distributive-constant framework, offering a broad tool for Diophantine finiteness in families of semi-decomposable forms.
Abstract
In this paper, we give some finiteness criteria for the solutions of the sequence of semi-decomposable form equations and inequalities, where the semi-decomposable form is factorized into a family of homogeneous polynomials with the distributive constant exceeding a certain number.
