In mathematics the Schur indicator, named after Issai Schur, or Frobenius–Schur indicator describes what invariant bilinear forms a given irreducible representation of a compact group on a complex vector space has. It can be used to classify the irreducible representations of compact groups on real vector spaces.
Read more about Frobenius–Schur Indicator: Definition, Real Irreducible Representations, Invariant Bilinear Forms, Higher Frobenius-Schur Indicators