Numerical criteria on the complex Hessian quotient equations with the Calabi symmetry
Rei Murakami
TL;DR
This work establishes a Calabi-symmetry–driven numerical criterion that guarantees solvability of the complex Hessian quotient equation on a compact Kähler manifold, in line with Székelyhidi's conjecture. By employing the Calabi ansatz, the PDE is reduced to a first-order nonlinear ODE, and a boundary-value problem with $y(0)=0$ and $y(b)=q$ is solved under the numerical condition, ensuring the eigenvalue data remain in the admissible cone $\Gamma_k$. The paper also proves the existence of strictly $\alpha$-$(\omega,k)$-subharmonic representatives in the semiample case, using an Iitaka-fibration–based perturbation scheme, and discusses the relation to $(n-k)$-positivity in Andreotti-Grauert theory via an appendix. Together, these results advance understanding of partial positivity in cohomology classes for complex Hessian-type equations and connect to broader positivity criteria in Kähler geometry.
Abstract
Assuming Calabi symmetry, we prove that a numerical condition ensures the solvability of the complex Hessian quotient equation, as conjectured by Székelyhidi. We also propose a conjecture on the existence of a $k$-subharmonic representative in a given cohomology class and confirm it under the assumption of Calabi symmetry or when the class is semiample.
