Modules and generalizations of Joyce vertex algebras

Joyce vertex algebras are vertex algebra structures defined on the homology of certain C-linear moduli stacks, and are used to express wall-crossing formulae for Joyce's homological enumerative invariants. This paper studies the generalization of this construction to settings that come from non-linear enumerative problems. In the special case of orthosymplectic enumerative geometry, we obtain twisted modules for Joyce vertex algebras. We expect that our construction will be useful for formulating wall-crossing formulae for enumerative invariants for non-linear moduli stacks. We include several variants of our construction that apply to different flavours of enumerative invariants, including Joyce's homological invariants, DT4 invariants, and a version of K-theoretic enumerative invariants.