Twisted Hodge diamonds give rise to non-Fourier-Mukai functors

TL;DR

This paper constructs numerous non-Fourier-Mukai functors using twisted Hodge diamonds and Hochschild cohomology, demonstrating their existence for odd-dimensional quadrics and arbitrary hypersurfaces.

Contribution

It introduces a method to produce non-Fourier-Mukai functors via twisted Hodge diamonds and Hochschild cohomology, expanding the known examples in algebraic geometry.

Findings

Existence of non-Fourier-Mukai functors for odd-dimensional quadrics.

Construction of non-Fourier-Mukai functors for arbitrary degree hypersurfaces.

Large class of Hochschild cohomology classes usable for such constructions.

Abstract

We apply computations of twisted Hodge diamonds to construct an infinite number of non-Fourier-Mukai functors with well behaved target and source spaces. To accomplish this we first study the characteristic morphism in order to control it for tilting bundles. Then we continue by applying twisted Hodge diamonds of hypersurfaces embedded in projective space to compute the Hochschild dimension of these spaces. This allows us to compute the kernel of the embedding into the projective space in Hochschild cohomology. Finally we use the above computations to apply the construction by A. Rizzardo, M. Van den Bergh and A. Neeman of non-Fourier-Mukai functors and verify that the constructed functors indeed cannot be Fourier-Mukai for odd dimensional quadrics. Using this approach we prove that there are a large number of Hochschild cohomology classes that can be used for this type construction. Furthermore, our results allow the application of computer-based calculations to construct candidate functors for arbitrary degree hypersurfaces in arbitrary high dimensions. Verifying that these are not Fourier-Mukai still requires the existence of a tilting bundle. In particular we prove that there is at least one non-Fourier-Mukai functor for every odd dimensional smooth quadric.