Left-invariant frame of the real Heisenberg group
= Left-invariant frame of the real Heisenberg group
For multiplication $(x,y,z)(a,b,c)=(x+a,y+b,z+c+xb)$, the left-invariant frame is
$$
E_1=\partial_x,\qquad E_2=\partial_y+x\partial_z,\qquad E_3=\partial_z.
$$
Its <Lie brackets of vector fields> satisfy $[E_1,E_2]=E_3$ and the other basis brackets vanish.