Reduction of Group Representations. V
John R. Gabriel · Journal of Mathematical Physics · 1971
This paper shows how to use information which can be obtained by use of the Todd Coxeter algorithm and related techniques, to reduce a group representation. The method reduces a representation of G given a reduction for a subgroup H of finite index in G. If the character table for G is given, only rational algebraic processes and square roots are used. If the character table for G is not known it can be found by solution of eigenvalue equations, using the class sums, which are obtained in the course of the calculation without scanning the whole group.