Character orthogonality and the S3 table
Research context
postgraduate concept · established · As of 2026-10-10
For complex finite-group representations, chi(g)=tr rho(g) is constant on conjugacy classes and irreducible characters are orthonormal under the group average.
Key knowledge
For complex finite-group representations, chi(g)=tr rho(g) is constant on conjugacy classes and irreducible characters are orthonormal under the group average. S3 has characters (1,1,1), (1,−1,1), (2,0,−1) on identity, transpositions and three-cycles, with class sizes 1,3,2. Their dimensions satisfy 1²+1²+2²=6; the two-dimensional representation is the zero-sum subspace of the permutation representation.
Values and equations
<chi,psi>=(1/|G|) sum_g chi(g) conjugate(psi(g))
- chi,psi
- Complex group characters
- G
- Finite group
Conditions and scope
- The orthogonality assertion is over C for a finite group.
- Class sizes weight the scalar product. A character table need not determine the group up to isomorphism.
Sources · 1
References
Sources retain their recorded scope. A source link alone does not establish verification of every statement.
Evidence and review
Author checked this English statement, displayed equation where present and stated hypotheses against these source locations: Chapter 7, matrix representations pp. 101–103, Maschke pp. 103–105, characters pp. 115–119. The check is bounded to the recorded claims; no complete proof reconstruction, software proof replay or universal literature completeness is claimed.
2026-10-10 · Author source-body/statement/equation/domain check, with graph associations scoped individually. Separate independent content/source/inventory review is required before branch closure.
Entry details
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- research-math-characters-s3
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