Dynkin index

In mathematics, the Dynkin index In mathematics, the Dynkin index of a representation with highest weight | λ | {displaystyle |lambda |} of a compact simple Lie algebra g {displaystyle {mathfrak {g}}} that has a highest weight λ {displaystyle lambda } is defined by evaluated in the representation | λ | {displaystyle |lambda |} . Here t a {displaystyle t_{a}} are the matrices representing the generators, and g a b {displaystyle g_{ab}} is given by