The Lie algebra L can be given either from its structure constants or from its infinitesimal generator representation.
DerivedSeries returns the sequence of ideals L^{(2)} L^{(i)} where, L^{(i+1)}=[L^{(i)}, L^{(i)}], i≥1 and L^{(1)}=L. The second argument specifies whether a portion or a specific member of the chain will be returned.