Weyl made a character formular for SU(m).
Let D1 and D2 be general irreps of SU(m).
kronecker product(D1,D2)= product of characters. There exists a unique decomposition as a sum of characters.
For g in SU(m) there exists h s.t. h^gh=diag(eigenvalues)=diag(e1,...,em) where ei = a pure phase (because of unitarity) and product(ei)=1.
Let Bij=ei^li, Cij=ei^(m-j) where li = number of boxes in the ith row of corresponding young tableau +m (dimension) -i.
X=character=det(B)/det(C)
if ei=1 => det(B)/det(C)= dim D