C₂-Cofiniteness and Rationality of the Icosahedral Orbifold V_L₂^A₅ · arXivDesk2608.13872Aug 14, 2026
C2-Cofiniteness and Rationality of the Icosahedral Orbifold VL2A5
Shun Xu
Abstract
Let L2=Zα be the rank-one root lattice with (α,α)=2, and let A5
act on the lattice vertex operator algebra
through an icosahedral subgroup of
Aut(VL2)≅PSL2(C) . We prove that the fixed-point vertex operator algebra
VL2A5 is
-cofinite and strongly rational.