2 papers
math.QA1999
Semi-affine Coxeter-Dynkin graphs and
John McKay
These graphs generalize both affine and finite type and provide an explanation for some quantum properties of roots of unity.
solv-int1999
Modular Invariants and Generalized Halphen Systems
J. Harnad, J. McKay
Generalized Halphen systems are solved in terms of functions that uniformize genus zero Riemann surfaces, with automorphism groups that are commensurable with the modular group. Ra…