Entire curves generating all shapes of Nevanlinna currents
报告人：谢松晏研究员（中科院）
时间：2023-11-22 15:30-16:30
地点：智华楼 方程教室（208）
Abstract: First, we show that every complex torus $\mathbb{T}$ contains some entire curve $g: \mathbb{C}\rightarrow \mathbb{T}$ such that the concentric holomorphic discs $\{g\restriction_{\overline{\mathbb D}_{r}}\}_{r>0}$ can generate all the Nevanlinna/Ahlfors currents on $\mathbb T$ at cohomological level. This confirms an anticipation of Sibony. Developing further our new method, we can construct some twisted entire curve $f: \mathbb{C}\rightarrow \mathbb{CP}^1\times E$ in the product of the rational curve $\mathbb{CP}^1$ and an elliptic curve $E$, such that, concerning Siu's decomposition, demanding any cardinality $|J|\in \mathbb{Z}_{\geqslant 0}\cup \{\infty\}$ and that $\mathcal{T}_{\mathrm{diff}}$ is trivial ($|J|\geqslant 1$) or not ($|J|\geqslant 0$), we can always find a sequence of concentric holomorphic discs $\{f\restriction_{\overline{\mathbb D}_{r_j}}\}_{j\geqslant 1}$ to generate a Nevanlinna/Ahlfors current $\mathcal{T}=\mathcal{T}_{\mathrm{alg}}+\mathcal{T}_{\mathrm{diff}}$ with the singular part $\mathcal{T}_{\mathrm{alg}}=\sum_{j\in J} \,\lambda_j\cdot[\mathsf C_j]$ in the desired shape. This fulfills the missing case where $|J|=0$ in the previous work of Huynh-Xie. By a result of Duval, each $\mathsf C_j$ must be rational or elliptic. We will show that there is no a priori restriction on the numbers of rational and elliptic components in the support of $\mathcal{T}_{\mathrm{alg}}$, thus answering a question of Yau and Zhou. Moreover, we will show that the positive coefficients $\{\lambda_j\}_{j\in J}$ can be arbitrary as long as the total mass of $\mathcal{T}_{\mathrm{alg}}$ is less than or equal to $1$. Our results foreshadow striking holomorphic flexibility of entire curves in Oka geometry, which deserves further exploration. This is joint work with Hao Wu (NUS).
