arXiv subjects

Jaime Negrete

Publications and source records attributed to Jaime Negrete.

3 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

Classification of wormhole singularities

We classify all wormhole singularities, i.e. cyclic quotient surface singularities admitting at least two extremal P-resolutions, thereby solving an open problem posed by Urz\'ua. Our approach introduces a new combinatorial framework based on what we call the coherent graph of a framed triangulated polygon. As an application, we give an alternative proof of the Hacking-Tevelev-Urz\'ua theorem on the maximum number of extremal P-resolutions of a cyclic quotient singularity.

math.AG↗

arXiv2024

Classification of Horikawa surfaces with T-singularities

We classify all projective surfaces with only T-singularities, ample canonical class, and $K^2=2p_g-4$. In this way, we identify all surfaces, smoothable or not, with only T-singularities in the Koll\'ar--Shepherd-Barron--Alexeev (KSBA) moduli space of Horikawa surfaces. We also prove that they are not smoothable when $p_g \geq 10$, except for the Lee-Park (Fintushel-Stern) examples, which we show to have only one deformation type unless $p_g=6$ (in which case they have two). This demonstrates that the challenging Horikawa problem cannot be addressed through complex T-degenerations. We propose new questions regarding diffeomorphism types based on our classification. Furthermore, the techniques developed in this paper enable us to classify all KSBA surfaces with only T-singularities and $K^2\leq 2p_g-3$, for example, quintic surfaces and I-surfaces.

math.AG↗