Vojta’s conjecture on rational surfaces and the abc conjecture

We prove Vojta’s conjecture for some rational surfaces. Moreover, for similar but different rational surfaces, we show that their Vojta’s conjecture is related to the abc conjecture. More specifically, we prove that Vojta’s conjecture on these surfaces implies a special case of the abc conjecture, while the abc conjecture implies Vojta’s conjecture on these surfaces. The argument carries over to the holomorphic case, so we unconditionally obtain Griffiths’ conjecture for the same situation. To prove these results, we prove and use some properties of Farey sequences.

Level structures on abelian varieties and Vojta’s conjecture

Assuming Vojta’s conjecture, and building on recent work of the authors, we prove that, for a fixed number field $K$ and a positive integer $g$, there is an integer $m_{0}$ such that for any $m>m_{0}$ there is no principally polarized abelian variety $A/K$ of dimension $g$ with full level-$m$ structure. To this end, we develop a version of Vojta’s conjecture for Deligne–Mumford stacks, which we deduce from Vojta’s conjecture for schemes.