On type II degenerations of hyperkähler manifolds

2021/08/03 by Daniel Huybrechts, Mirko Mauri, Huybrechts, Daniel +1 · 1 citation
Mathematics · #Geometry and complex manifolds #Algebraic Geometry and Number Theory #Advanced Algebra and Geometry

paper · pdf · doi:10.48550/arxiv.2108.01587

Abstract

We give a simple argument to prove Nagai's conjecture for type II degenerations of compact hyperkähler manifolds and cohomology classes of middle degree. Under an additional assumption, the techniques yield the conjecture in arbitrary degree. This would complete the proof of Nagai's conjecture in general, as it was proved already for type I degenerations by Kollár, Laza, Saccà, and Voisin and independently by Soldatenkov, while it is immediate for type III degenerations. Our arguments are close in spirit to a recent paper by Harder proving similar results for the restrictive class of good degenerations.

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• Arithmetic monodromy of hyper-Kähler varieties over p-adic fields

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