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Wern Yeong

Publications and source records attributed to Wern Yeong.

8 recordsLinked to original sources
arXiv2026

Pseudo-hyperbolicity of Horikawa surfaces

Horikawa surfaces are minimal complex algebraic surfaces of general type with minimal Chern slope, satisfying either $c_2=5c^2_1+36$ if $c_1^2$ is even, or $c_2=5c^2_1+30$ if $c_1^2$ is odd. We prove that very general Horikawa surfaces with $p_g\ge 5$ contain only finitely many rational or elliptic curves. Moreover, we provide an explicit characterization and count of these curves. Our results also apply to very general Horikawa surfaces of the first kind with $p_g\in \{3,4\}.$

math.AG↗
arXiv2025

Hyperbolicity of adjoint linear series on varieties with positive tangent bundle

Let $X$ be a smooth projective variety of dimension $n\geq 3$, and let $L$ be an ample line bundle on $X$. In this article, we study the algebraic hyperbolicity of a very general section of the adjoint linear series $|K_X+mL|$ when the tangent bundle $T_X$ of $X$ has suitable positivity properties. As a consequence, we show that the linear system $|K_X+mL|$ is hyperbolic (or pseudo-hyperbolic) for $m\geq 3n+1$, for various classes of polarized pairs $(X,L)$, thus providing new evidence of a conjecture that was proposed by the second and fourth authors. Moreover, when $X$ is abelian, we show that the linear system $|mL|$ is hyperbolic for $m\geq n$, and the same holds when $m\geq n-1$, if $|L|$ has no base divisors. It turns out that these bounds for abelian varieties are sharp. We also prove analogous statements for Kummer varieties and certain classes of hyperelliptic varieties.

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arXiv2024

A hyperbolicity conjecture for adjoint bundles

Let $X$ be a $n$-dimensional smooth projective variety and $L$ be an ample Cartier divisor on $X$. We conjecture that a very general element of the linear system $|K_X+(3n+1)L|$ is a hyperbolic algebraic variety. This conjecture holds for some classical varieties: surfaces, products of projective spaces, and Grassmannians. In this article, we investigate the conjecture for $X$ a toric variety. We confirm the conjecture in the case of smooth projective toric varieties. When $X$ is a Gorenstein toric variety, we show that $|K_X+(3n+1)L|$ is pseudo hyperbolic. For a Gorenstein toric threefold $X$, we show that $|K_X+9L|$ is hyperbolic.

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arXiv2024

Polarized endomorphisms of log Calabi-Yau pairs

Let $(X,\Delta)$ be a dlt log Calabi-Yau pair admitting a polarized endomorphism. We show that $(X,\Delta)$ is a finite quotient of a toric log Calabi-Yau fibration over an abelian variety. We provide an example which shows that the previous statement does not hold if we drop the dlt condition of $(X,\Delta)$ even if $X$ is a smooth variety. Given a klt type variety $X$ and a log Calabi-Yau pair $(X,\Delta)$ admitting a polarized endomorphism, we show that a suitable birational modification of $(X,\Delta)$ is a finite quotient of a toric log Calabi-Yau fibration over an abelian variety.

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arXiv2024

Polarized endomorphisms of Fano varieties with complements

Let $X$ be a Fano type variety and $(X,Δ)$ be a log Calabi-Yau pair with $Δ$ a Weil divisor. If $(X,Δ)$ admits a polarized endomorphism, then we show that $(X,Δ)$ is a finite quotient of a toric pair. Along the way, we prove that a klt Calabi-Yau pair $(X,Δ)$ with standard coefficients that admits a polarized endomorphism is the quotient of an abelian variety.

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arXiv2023

Algebraic Hyperbolicity of Complements of Generic Hypersurfaces in Projective Spaces

We study the algebraic hyperbolicity of the complement of very general degree $2n$ hypersurfaces in P^n. We prove the Algebraic Green-Griffiths-Lang Conjecture for these complements, and in the case of the complement of a quartic plane curve, we completely characterize the exceptional locus as the union of the flex and bitangent lines.

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arXiv2022

Algebraic hyperbolicity of very general hypersurfaces in products of projective spaces

We study the algebraic hyperbolicity of very general hypersurfaces in $\mathbb{P}^m \times \mathbb{P}^n$ by using three techniques that build on past work by Ein, Voisin, Pacienza, Coskun and Riedl, and others. As a result, we completely answer the question of whether or not a very general hypersurface of bidegree $(a,b)$ in $\mathbb{P}^m \times \mathbb{P}^n$ is algebraically hyperbolic, except in $\mathbb{P}^3 \times \mathbb{P}^1$ for the bidegrees $(a,b)= (7,3), (6,3)$ and $(5,b)$ with $b\geq 3.$ As another application of these techniques, we improve the known result that very general hypersurfaces in $\mathbb{P}^n$ of degree at least $2n-2$ are algebraically hyperbolic when $n\geq 6$ to $n \geq 5$, leaving $n=4$ as the only open case.

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