Flatness of Tensor Products and Semi-Rigidity for $C_2$-cofinite Vertex Operator Algebras II
Abstract
Let V be a simple C_2-cofinite VOA of CFT-type and we assume that there is a simple module U such that \Hom_V(U\boxtimes V',V)\not=0 where V' is a restricted dual of V. As the author has shown, an S-transformation S(\Psi_V) of a trace function \Psi_V on V corresponding \begin{pmatrix}0&-1\cr 1&0\end{pmatrix} may contain pseudo-trace functions. Our assumption in this paper is that no pseudo-trace functions appear in S(\Psi_V). Under these assumptions, we prove that every V-module W is semirigid and \Psi_W appears in S(\Psi_V). As a corollary of our main theorem, a fixed point subVOA of a rational VOA of CFT-type by an automorphism of finite order becomes rational if fixed point subVOA is C_2-cofinite.
Keywords
Cite
@article{arxiv.0909.3665,
title = {Flatness of Tensor Products and Semi-Rigidity for $C_2$-cofinite Vertex Operator Algebras II},
author = {Masahiko Miyamoto},
journal= {arXiv preprint arXiv:0909.3665},
year = {2010}
}
Comments
14 pages, we avoid the calculations of fusion matrices, we need one assumption to avoid pseudo-trace function, and we also add a proof of the semisimplicity of orbifold models of rational VOAs