Basic Albanese maps of regular Riemannian foliations
Kinga Słowik, Robert Wolak
TL;DR
The paper defines the basic Albanese map for foliated Riemannian manifolds via basic 1-forms and connects it to the classical Albanese map through the first basic cohomology $H^1(M/\mathcal{F})$. It develops a cohomological framework using Molino theory to relate rational and integer basic first cohomology, proves universal and harmonic properties of the basic Albanese map, and analyzes the submersion case and nilmanifold applications. It also extends to singular Riemannian foliations, showing that the dimension of $H^1(M/\mathcal{F})$ controls the stratified codimensions of leaf closures and constrains possible leaf behaviors. Together these results provide a robust tool for understanding foliated geometry via basic cohomology and harmonic maps to flat tori, with concrete examples on nilmanifolds and Iwasawa-type manifolds.
Abstract
In the paper we introduce the notion of basic Albanese map which we define for foliated Riemannian manifolds using basic 1-forms. We relate this mapping to the classical Albanese map for the ambient manifold. The study of general properties is supplemented with the description of several important examples.
