Information About

Coroot




In Mathematics , a coroot is a certain kind of element of Cartan Subalgebra of a complex Semisimple Lie Algebra ''g''.

The structure and representation theory of ''g'' is characterised by its Root System . Given a root, α of a ''g'', there are associated to it two Operator s;

:X_{\alpha}

and

:Y_{\alpha},

known as the raising and lowering operators respectively.

Their Lie bracket,

: H_{\alpha} = Y_{\alpha}
is an element of the Cartan subalgebra.


These raising and lowering operators are determined only up to scalar multipliers. It is often useful to set their lengths so as to form a subalgebra isomorphic to

sl


the Lie algebra of the Special Linear Group , of dimension 3.

Once this has been done

: H_{\alpha}

is the ''coroot'' associated to α (French ''copoid'').