Past exam of the mathematics course of the University of Cambridge 2016 iii Paper 103 4 b iii Solution Created 2026-10-03 Updated 2026-10-06
There are -cycles in , and each has the same character value of a representation on . Taking traces in the cycle-sum identity for Young–Jucys–Murphy elements yieldsOnly tableaux whose first entries form a hook partition contribute.
Write such a shape as , for . There are ways to fill it: choose which of the labels go below the first box. There are ways to fill the remaining skew diagram with the labels , in standard order. The eigenvalue from part (ii) is , so the factoris . Therefore the general character value isHere counts standard skew Young tableaux, and is zero when is not contained in . In particular, for a full -cycle,For , the general formula gives , the character value at the identity, as it should.