K\'ahler spaces with zero first Chern class: Bochner principle, Albanese map and fundamental groups

Autor: Claudon, Benoît, Graf, Patrick, Guenancia, Henri, Naumann, Philipp
Rok vydání: 2020
Předmět:
Druh dokumentu: Working Paper
DOI: 10.1515/crelle-2022-0001
Popis: Let $X$ be a compact K\"ahler space with klt singularities and vanishing first Chern class. We prove the Bochner principle for holomorphic tensors on the smooth locus of $X$: any such tensor is parallel with respect to the singular Ricci-flat metrics. As a consequence, after a finite quasi-\'etale cover $X$ splits off a complex torus of the maximum possible dimension. We then proceed to decompose the tangent sheaf of $X$ according to its holonomy representation. In particular, we classify those $X$ which have strongly stable tangent sheaf: up to quasi-\'etale covers, these are either irreducible Calabi--Yau or irreducible holomorphic symplectic. As an application of these results, we show that if $X$ has dimension four, then it satisfies Campana's Abelianity Conjecture.
Comment: 28 pages; v2: exposition improved following the referee's suggestions, new title, section 7 shortened and section 8 removed; to appear in Crelle
Databáze: arXiv