Torus chiral \(n\)-point functions for free boson and lattice vertex operator algebras.

*(English)*Zbl 1020.17020Given a vertex operator algebra (VOA) \(V\) one may define chiral \(n\)-point functions at genus one following Y. Zhu [J. Am. Math. Soc. 9, 237-302 (1996; Zbl 0854.17034)] and then use various sewing procedures to define such functions at higher genera. However, these procedures require a detailed description of the genus one \(n\)-point functions. In the paper under review the authors obtain explicit expressions for all genus one \(n\)-point functions in two important cases, namely when \(V\) is either a Heisenberg VOA (also called a free boson theory) or a lattice VOA, that is, a VOA associated to a positive-definite, even lattice. Roughly speaking, in a free boson theory the \(n\)-point functions are elliptic functions whose structure depends on certain combinatorial data determined by the states in \(V\) under consideration. In the case of a lattice VOA, the function is the product of two pieces, one determined by the Heisenberg sub-VOA of \(V\) and one which may be described in terms of the lattice itself and the genus one prime form. The paper concludes with a discussion of \(n\)-point functions from the point of view of their symmetry and elliptic properties.

Reviewer: Julius Borcea (Stockholm)