10. Let A denote the k-algebra on four generators x, ..., 4 with defining relations X1 X2 QX 2X1 = x, x2x3 = qx3X2, X3 X4 qx 4x3, X4X2 qx2x4, where q k* with q dimension of A. X1X3 qx3x1 = x, xxqxx = x, X1X4 = = 1. Prove that A is an iterated Ore extension of k and find the GK-