210323 Martijn Kool

Solid partitions are piles of boxes in the corner of a 4-dimensional room. Their enumeration is a mystery since MacMahon proposed an incorrect formula around 1916. Motivated by super-Yang-Mills theory on (complex) 4-dimensional affine space, Nekrasov recently assigned a measure to solid partitions and proposed a conjectural formula for their weighted enumeration.

We give a geometric definition of this measure using the Hilbert scheme of points on 4-dimensional affine space. Although this Hilbert scheme is very singular and has “higher obstruction spaces”, we can use recent work of Oh-Thomas to localise our invariants and prove Nekrasov’s conjecture. Joint work with J. V. Rennemo.