C_2-cofiniteness of cyclic-orbifold models

Understand

We prove an orbifold conjecture for a solvable automorphism group.

• Namely, we show that if V is a C_2-cofinite simple vertex operator algebra and G is a finite solvable automorphism group of V, then the fixed point vertex operator subalgebra V^G is also C_2-cofinite.
• This offers a mathematically rigorous background to orbifold theories of finite type with solvable automorphism groups.