Unit · year 4
MU-402 · Representation Theory
Threads structure4 theorems
Groups realised as symmetries of vector spaces.
Theorems in this unit
T-122
Maschke's theorem
Representations of finite groups over C are completely reducible.
T-123
Schur's lemma
Morphisms between irreducibles are zero or isomorphisms.
T-124
Orthogonality of characters
Irreducible characters form an orthonormal set.
T-125
Burnside's counting lemma
Orbits counted by average fixed points.