Chiral Hodge Cohomology and Mathieu Moonshine

We construct a filtration of chiral Hodge cohomolgy of a K3 surface $X$, such that its associated graded object is a unitary representation of the $\mathcal{N}=4$ superconformal vertex algebra with central charge $c=6$ and its subspace of primitive vectors has the property; its equivariant character for a symplectic automorphism $g$ of finite order acting on $X$ agrees with the McKay–Thompson series for $g$ in Mathieu moonshine.