DT invariants from vertex algebras
Vladimir Dotsenko, Sergey Mozgovoy
TL;DR
The paper develops a unified framework linking cohomological Hall algebras for symmetric quivers with vertex (and conformal) algebras by showing that the graded dual $\\mathcal H_Q^{\vee}$ carries a natural cocommutative vertex bialgebra structure and is isomorphic to the universal enveloping vertex algebra of a vertex Lie algebra $C$. This identification explains the CoHA product as a shuffle product arising from the principal free vertex algebra associated to the Euler form $\\chi$ of the quiver, and it yields a new, conceptually clear proof of the positivity of refined Donaldson–Thomas invariants via $C/\\partial C$. The work also provides new descriptions and spanning sets for CoHA-modules (non-commutative Hilbert schemes) and develops a framework to relate CoHA-modules to free vertex algebras through modified coproducts and coactions. Collectively, these results illuminate deep structural connections between CoHAs, vertex algebras, and DT theory, offering a path toward Koszul duality perspectives and potential generalizations to quivers with potentials."
Abstract
We obtain a new interpretation of the cohomological Hall algebra $\mathcal{H}_Q$ of a symmetric quiver $Q$ in the context of the theory of vertex algebras. Namely, we show that the graded dual of $\mathcal{H}_Q$ is naturally identified with the underlying vector space of the principal free vertex algebra associated to the Euler form of $Q$. Properties of that vertex algebra are shown to account for the key results about $\mathcal{H}_Q$. In particular, it has a natural structure of a vertex bialgebra, leading to a new interpretation of the product of $\mathcal{H}_Q$. Moreover, it is isomorphic to the universal enveloping vertex algebra of a certain vertex Lie algebra, which leads to a new interpretation of Donaldson--Thomas invariants of $Q$ (and, in particular, re-proves their positivity). Finally, it is possible to use that vertex algebra to give a new interpretation of CoHA modules made of cohomologies of non-commutative Hilbert schemes.
