Solution
= Solution
The Lie algebra consists of strictly upper-triangular matrices
$$
X=qQ+rR+sS,
\quad Q=E_{12},\quad R=E_{23},\quad S=E_{13}.
$$
The only nonzero basis bracket is $[Q,R]=S$. Thus the independent nonzero <structure constant of a Lie algebra> values are $f_{QR}{}^S=1$ and $f_{RQ}{}^S=-1$.