Real phase structures on tropical manifolds and patchworks in higher codimension

Abstract

This paper generalises the homeomorphism theorem behind Viro's combinatorial patchworking of hypersurfaces in toric varieties to arbitrary codimension using tropical geometry. We first define the patchwork of a polyhedral space equipped with a real phase structure. When the polyhedral subspace is tropically non-singular, we show that the patchwork is a topological manifold. When a non-singular tropical variety appears as a tropical limit of a real analytic family, we show that the real part of a fibre of the family near the tropical limit is homeomorphic to the patchwork. Finally we extend the spectral sequence introduced by the last two authors in the case of hypersurfaces to non-singular tropical varieties with real phase structures. As a corollary, we obtain bounds on the Betti numbers of the patchwork in terms of the dimensions of the tropical homology groups with coefficients modulo two.