“…This algebra has a non-degenerate associative form k (see [11,Theorem 7]), defined by the same formula given above for H{2 : n;co 0 ) with, in addition, k(xy, xy) -1 and k(-, •) = 0 in all remaining cases. Again from [7] (or the original source [41,Theorem 3.2]), all outer derivations of H(2 : n;<w 2 ) are lifted from part of those of its associated graded algebra, which is H(2 : n\co 0 ) © {xy). Specifically, a basis for the space of outer derivations of H(2 : n;o> 2 ) is given by (adjt) p ' forO < r < n 2 and (ady) p ' forO < 5 < n,.…”