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Generating all Ahlfors currents by a single entire curve

Yunling Chen, John Erik Fornæss, Song-Yan Xie

TL;DR

This work resolves Sibony's conjecture for weak Oka-1 manifolds by constructing an entire curve $F:\mathbb{C}\to X$ whose concentric discs generate all Ahlfors currents on $X$ under the Runge approximation on discs. The authors combine a holomorphic gluing technique, a novel ping-pong induction, and a careful inductive limiting process to amalgamate a countable family of discs into concentric discs from a single $F$, ensuring precise length-area and cohomology control. Central to the approach are a countable disc family generating all Ahlfors currents (via Xie24) and a shrinking-dumbbell lemma with Carathéodory kernel convergence that enables precise current convergence. The result highlights the extraordinary flexibility of entire curves in the weak Oka-1 setting and lays groundwork for potential extensions to Nevanlinna currents and broader Oka-type phenomena.

Abstract

Let \(X\) be a compact complex manifold possessing the \emph{Runge approximation property on discs}, meaning that every holomorphic map from a closed disc into \(X\) is approximable by a global holomorphic map from \(\mathbb{C}\). We construct an entire curve \(F : \mathbb{C} \to X\) such that the associated family of concentric holomorphic discs \(\{F|_{\overline{\mathbb{D}}_r}\}_{r>0}\) generates all Ahlfors currents on \(X\), thereby settling a conjecture of Sibony.

Generating all Ahlfors currents by a single entire curve

TL;DR

This work resolves Sibony's conjecture for weak Oka-1 manifolds by constructing an entire curve whose concentric discs generate all Ahlfors currents on under the Runge approximation on discs. The authors combine a holomorphic gluing technique, a novel ping-pong induction, and a careful inductive limiting process to amalgamate a countable family of discs into concentric discs from a single , ensuring precise length-area and cohomology control. Central to the approach are a countable disc family generating all Ahlfors currents (via Xie24) and a shrinking-dumbbell lemma with Carathéodory kernel convergence that enables precise current convergence. The result highlights the extraordinary flexibility of entire curves in the weak Oka-1 setting and lays groundwork for potential extensions to Nevanlinna currents and broader Oka-type phenomena.

Abstract

Let be a compact complex manifold possessing the \emph{Runge approximation property on discs}, meaning that every holomorphic map from a closed disc into is approximable by a global holomorphic map from . We construct an entire curve such that the associated family of concentric holomorphic discs generates all Ahlfors currents on , thereby settling a conjecture of Sibony.

Paper Structure

This paper contains 10 sections, 11 theorems, 45 equations, 3 figures.

Key Result

Theorem 1.4

Let $X$ be a compact complex manifold satisfying the weak Oka-1 property. Then there exists an entire curve $f \colon \mathbb{C} \to X$ whose associated holomorphic discs $\{f|_{\overline{\mathbb{D}}(a,r)}\}_{a\in\mathbb{C},\, r>0}$ generate all Nevanlinna and Ahlfors currents on $X$.

Figures (3)

  • Figure 1: Dumbbell-shaped neighborhood of $D_1$ and $D_2$.
  • Figure 2: Dumbbell domain convergence.
  • Figure 3: Conformal map from dumbbell domain to disc.

Theorems & Definitions (22)

  • Conjecture 1.2
  • Definition 1.3: Xie24
  • Theorem 1.4: Xie24
  • Theorem 1.5: WuXie25
  • Definition 1.6
  • Definition 1.7
  • Theorem 1.8: Main Theorem
  • Theorem 2.1
  • Definition 2.2: cf. FornaessForstnericWold20
  • Theorem 2.3: Mergelyan theorem for manifold-valued maps on admissible sets; cf. AlarconForstneric21
  • ...and 12 more