Torus link homology and the nabla operator

Abstract

In recent work, Elias and Hogancamp develop a recurrence for the Poincaré series of the triply graded Hochschild homology of certain links, one of which is the $(n,n)$ torus link. In this case, Elias and Hogancamp give a combinatorial formula for this homology that is reminiscent of the combinatorics of the modified Macdonald polynomial eigenoperator $\nabla$. We give a combinatorial formula for the homologies of all links considered by Elias and Hogancamp. Our first formula is not easily computable, so we show how to transform it into a computable version. Finally, we conjecture a direct relationship between the $(n,n)$ torus link case of our formula and the symmetric function $\nabla p_{1^n}$.