Several Nonarchimedean Variables, Isolated Periodic Points, and Zhang's Conjecture
Several Nonarchimedean Variables, Isolated Periodic Points, and Zhang's Conjecture
Please note special day, time, and location. We study dynamical systems in several variables over a complete valued field. If x is a fixed point, we show that in many cases there exist fixed analytic subvarieties through x. These cases include all cases in which x is attracting in some directions and repelling in others, which lets us separate attracting, repelling, and indifferent directions, generalizing results from complex hyperbolic dynamics. We use this for two purposes: first, we show that over the p-adics, if x has no repelling directions, then it is isolated, that is there exists a p-adic neighborhood of x containing no other periodic points; and second, we prove some cases of a conjecture of Shouwu Zhang that every reasonable dynamical system defined over a number field has a point defined over Q-bar with a Zariski-dense forward orbit.