On Vojta's proof of the Mordell conjecture
Xinyi Yuan
TL;DR
The paper reframes Vojta's original Mordell conjecture proof within Arakelov geometry, replacing Gillet–Soulé's arithmetic Riemann–Roch with Yuan's arithmetic Siu inequality. It constructs a small section of a high multiple of a Vojta line bundle using arithmetic Siu to obtain a height lower bound, and then derives a lower bound for the point heights via a careful analysis of vanishing indices. The index is controlled using a classical Dyson-type lemma (via three reductions and a blow-up argument), completing the chain that yields Vojta's inequality and the finiteness of $C(K)$. The approach preserves the Arakelov-geometric spirit while avoiding the arithmetic Riemann–Roch step, offering a streamlined route to Faltings' theorem and related uniform bounds in Diophantine geometry.
Abstract
This paper re-organizes Vojta's proof of the Mordell conjecture (i.e. Faltings' theorem) in terms of Arakelov geometry. A new ingredient is to replace an application of Gillet--Soule's arithmetic Riemannn--Roch theorem by that of Yuan's arithmetic Siu inequality.
