Modular Invariance of Characters for Affine Lie Algebras at Subprincipal Admissible Levels

Key Points

• The span of normalized characters for subprincipal admissible modules is invariant under SL2 transformations.
• We find an explicit formula for modular transformations involving characters of affine lie algebras.
• The study focuses on modules at subprincipal admissible levels, showing significant algebraic implications.
• Results enhance understanding of the structure and symmetry of characters in affine lie algebras.