Topological adelic curves: Zariski-Riemann spaces, algebraic coverings, Harder-Narsimhan filtrations and heights

Abstract

In this article, we introduce topological adelic curves. Roughly speaking, a topological adelic curve is a topological space of (generalised) absolute values on a given field satisfying a product formula. Topological adelic curves are the topological counterpart to adelic curves introduced by Chen and Moriwaki. They aim at handling Arakelov geometry over possibly uncountable fields and give further ideas in the formalisation of the analogy between Diophantine approximation and Nevanlinna theory. Using the notion of pseudo-absolute values developed in arXiv:2411.03905, we prove several fundamental properties of topological adelic curves: algebraic coverings, existence of Harder-Narasimhan filtrations and of volume functions. We also define heights of cycles and give a generalisation of Nevanlinna's first main theorem in this framework. Another important feature of topological adelic curves is that they come equipped with Zariski-Riemann type spaces that admit a natural locally ringed space structure and usual Arakelov theoretic objects (e.g. adelic vector bundles) admit a natural interpretation in terms of metrised objects on these Zariski-Riemann spaces.