Positive characteristic Ax-Schanuel
Piotr Kowalski
TL;DR
This expository article surveys Ax-Schanuel type statements across characteristic zero and positive characteristic, framing the problem around the interplay of analytic, differential, and formal maps. It presents the classical characteristic-zero landscape (Schanuel’s conjectures, Ax’s differential theorem, and the dimension-intersection results) and then introduces the first positive-characteristic Ax-Schanuel result for additive power series, along with a broad conjectural framework using formal maps and good one-dimensional groups. The piece outlines two major directions for unifying Ax-Schanuel phenomena: a general connection-based formulation in characteristic zero (and its potential positive-characteristic analogues) and the development of Hasse-Schmidt differential Ax-Schanuel statements in positive characteristic. Collectively, the work highlights potential Diophantine and model-theoretic applications and charts pathways for extending Ax-Schanuel theory beyond characteristic zero through formal and HS-derivation methods. The article also situates these ideas within the broader context of Drinfeld modules, modular Ax-Schanuel, and ongoing research into general conjectures governing Ax-like transcendence phenomena.
Abstract
This expository paper is written in celebration of Boris Zilber's 75th birthday. We discuss Ax-Schanuel type statements focusing on the case of positive characteristic.
