Solution

ID: past-exam-of-the-lie-algebras-and-representation-theory-of-symmetric-groups-course-of-the-university-of-oxford/2007/b/5/d/solution

For shape with , there are exactly two removable rim hooks of size two: the bottom row, leaving , and the final two cells of the first row, leaving . Both have height zero. A vertical pair cannot be removed while leaving a Young diagram because the first row is longer than the second by at least two.
By the Murnaghan–Nakayama rule and part (b),

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