arXiv subjects

Woohyeok Jo

Publications and source records attributed to Woohyeok Jo.

4 recordsLinked to original sources

arXiv2026

The Algebraic Montgomery-Yang Problem

We completely resolve the algebraic Montgomery - Yang problem, a conjecture of Kollar stating that every rational homology projective plane with quotient singularities and a simply-connected smooth locus has at most three singular points. The crux of our proof is a new lattice theoretic constraint, obtained by combining Donaldson's diagonalization theorem with the distinguished spin^c structure on the smooth locus whose determinant line bundle is the canonical bundle. Together with the orbifold Bogomolov - Miyaoka - Yau inequality, this constraint rules out all remaining cases in the problem and completes the proof.

math.AG↗

arXiv2024

On lens spaces bounding smooth 4-manifolds with $\boldsymbol{b_2=1}$

We study which lens spaces can bound smooth 4-manifolds with second Betti number one under various topological conditions. Specifically, we show that there are infinite families of lens spaces that bound compact, simply-connected, smooth 4-manifolds with second Betti number one, yet cannot bound a 4-manifold consisting of a single 0-handle and 2-handle. Additionally, we establish the existence of infinite families of lens spaces that bound compact, smooth 4-manifolds with first Betti number zero and second Betti number one, but cannot bound simply-connected 4-manifolds with second Betti number one. The construction of such 4-manifolds with lens space boundaries is motivated by the study of rational homology projective planes with cyclic quotient singularities.

math.GT↗

arXiv2024

On rational homology projective planes with quotient singularities of small indices

In this article, we study the effects of topological and smooth obstructions on the existence of rational homology complex projective planes that admit quotient singularities of small indices. In particular, we provide a classification of the types of quotient singularities that can be realized on rational homology complex projective planes with indices up to three, whose smooth loci have trivial first integral homology group.

math.GT↗

arXiv2024

Algebraic Montgomery-Yang problem and smooth obstructions

Let $S$ be a rational homology complex projective plane with quotient singularities. The algebraic Montgomery-Yang problem conjectures that the number of singular points of $S$ is at most three if its smooth locus is simply-connected. In this paper, we leverage results from the study of smooth 4-manifolds, including the Donaldson diagonalization theorem and Heegaard Floer correction terms, to establish additional conditions for $S$. As a result, we eliminate the possibility of a rational homology complex projective plane of specific types with four singularities. Moreover, we identify large families encompassing infinitely many types of singularities that satisfy the orbifold BMY inequality, a key property in algebraic geometry, yet are obstructed from being a rational homology complex projective plane due to smooth conditions. Additionally, we discuss computational results related to this problem, offering new insights into the algebraic Montgomery-Yang problem.

math.GT↗