$T$-stability for Higgs sheaves over compact complex manifolds

TL;DR

This paper introduces a new concept of T-stability for Higgs sheaves on compact complex manifolds, establishing its properties, relations to existing stability notions, and implications for Hermitian-Yang-Mills metrics.

Contribution

It generalizes T-stability to Higgs sheaves, proves key properties, and links it with omega-stability and Hermitian-Yang-Mills metrics.

Findings

T-stability is preserved under dualization and tensoring with Higgs line bundles.

Omega-stability implies T-stability for torsion-free Higgs sheaves.

T-stability leads to the existence of Hermitian-Yang-Mills metrics on T-stable sheaves.

Abstract

We introduce the notion of $T$-stability for torsion-free Higgs sheaves as a natural generalization of the notion of $T$-stability for torsion-free coherent sheaves over compact complex manifolds. We prove similar properties to the classical ones for Higgs sheaves. In particular, we show that only saturated flags of torsion-free Higgs sheaves are important in the definition of $T$-stability. Using this, we show that this notion is preserved under dualization and tensor product with an arbitrary Higgs line bundle. Then, we prove that for a torsion-free Higgs sheaf over a compact K\"ahler manifold, $\omega$-stability implies $T$-stabilty. As a consequence of this we obtain the $T$-semistability of any reflexive Higgs sheaf with an admissible Hermitian-Yang-Mills metric. Finally, we prove that $T$-stability implies $\omega$-stability if, as in the classical case, some additional requirements on the base manifold are assumed. In that case, we obtain the existence of admissible Hermitian-Yang-Mills metrics on any $T$-stable reflexive sheaf.