Given virtual characters ch1 and ch2, the method computes the character of the tensor product of corresponding virtual representations of the symmetric group.
i1 : ch1 = new ClassFunction from {{4,4} => 2, {8} => -1, {5,2,1} => 2, {3,2,2,1} => 1};
i2 : ch2 = new ClassFunction from {{2,2,2,2} => -4, {5,2,1} => 1, {3,2,2,1} => 3};