The Lie algebra L can be provided either from their structure constants or their infinitesimal generator representation. Depending on that, the resulting subalgebra will be expresses as linear combination of the base elements using either the symbolic notation, with X[i] denoting ith base element of the Lie algebra or, by their infinitesimal generator representation.
Levi subalgebra is the semi simple algebra that arises from the Levi decomposition of a Lie algebra. It is not unique.
EXAMPLES
Basic Examples 
