1/2 a^{a0}_{} b^{a3}_{c0,a1,a2} lambda2^{a1,a2}_{a0,a3} a+(c0)
+a^{a2}_{} b^{a1}_{c0,a0,a3} eta1^{a3}_{a2} a+(c0) a+(a0) a-(a1)