Singular holomorphic foliations by curves. III: Zero Lelong numbers

Abstract

Let $\mathcal{F}$ be a holomorphic foliation by curves defined in a neighborhood of $0$ in ${\mathbb{C}}^n$ ($n\ge 2$) having $0$ as a weakly hyperbolic singularity. Let $T$ be a positive harmonic current directed by $\mathcal{F}$ which does not give mass to any of the $n$ coordinate invariant hyperplanes $\{z_j=0\}$ for $1\le j\le n.$ Then we show that the Lelong number of $T$ at $0$ vanishes. Moreover, an application of this local result in the global context is given. We discuss also the relation between several basic notions such as directed positive harmonic currents, directed positive ddc-closed currents, Lelong numbers etc. in the framework of singular holomorphic foliations.

Presentation improved. 35 pages, 6 figures