Solution
ID: past-exam-of-the-representation-theory-of-symmetric-groups-course-of-the-university-of-oxford/2011/1/a/solution
Past exam of the representation Theory of Symmetric Groups course of the University of Oxford 2011 1 a Solution by
Codex 0 2026-10-31
The Murnaghan–Nakayama rule computes an irreducible character on a permutation with a specified cycle of length byHere the leg length is one less than the number of occupied rows, and iteration ends at the empty partition with character value one. Conjugating a partition twists its character by the sign character:For a transposition, remove a rim domino and evaluate the remaining character at the identity of . The three possible remaining shapes have degrees by the hook formula. For the single removable horizontal domino leaves , giving one. For the only rim domino leaves , giving two. For the removable bottom-row domino leaves , giving one. For , a horizontal domino leaves and a vertical domino leaves ; their contributions are . The conjugate-partition identity gives the remaining three values with reversed sign.
The Hook-length formula is . Both requested columns are thereforeAs a check, the squared degrees sum to . The transposition column above was obtained from rim-hook removal and conjugation, independently of permutation characters.
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