Galois groups in rational conformal field theory II. The discriminant

Doron Gepner
2007 Physics Letters B  
We express the discriminant of the polynomial relations of the fusion ring, in any conformal field theory, as the product of the rows of the modular matrix to the power -2. The discriminant is shown to be an integer, always, which is a product of primes which divide the level. Detailed formulas for the discriminant are given for all WZW conformal field theories.
doi:10.1016/j.physletb.2007.08.054 fatcat:ds34ye2xcnh7tesjaxewlf4gbq