2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/227343We study a natural Hodge module on the Hilbert scheme of four points on affine three-space, which categorifies the Donaldson--Thomas invariant of the Hilbert scheme. We determine the weight filtration on the Hodge module explicitly in terms of intersection cohomology complexes, and compute the E-polynomial of its cohomology. The computations make essential use of a description of the singularity of the Hilbert scheme as the degeneracy locus of the Pfaffian function.22 pagesAlgebraic Geometry14C30, 14F25, 32S40The Milnor fibre of the Pfaffian and the Hilbert scheme of four points on C^3text