“…It is easy to see that the linear isometry from (h 1 , ·, · ) onto (h 1 , ·, · ′ ) mapping X 1 , X 2 , X 3 into X ′ 1 , X ′ 2 , X 3 respectively, lifts to an isometry from (H 1 , ·, · ) onto (H 1 , ·, · ′ ). Recall that the above argument fails in higher dimensions (see [Vuk15]). In fact, given an inner product ·, · on the (2n + 1)-dimensional Heisenberg Lie algebra h n , we decompose as an orthogonal sum h n = v ⊕ z and for every Z ∈ z we have associated the element j(Z) ∈ so(v) given by j(Z)X, Y = [X, Y ], Z .…”