1/4 a^{a0,a1}_{} b^{c0,c1}_{a2,a3} eta1^{a3}_{a1} eta1^{a2}_{a0} a-(c1) a-(c0)
+1/8 a^{a0,a1}_{} b^{c0,c1}_{a2,a3} lambda2^{a2,a3}_{a0,a1} a-(c1) a-(c0)
-1/2 a^{a0,a2}_{} b^{c0,c1}_{a1,a3} eta1^{a3}_{a2} a+(a1) a-(a0) a-(c1) a-(c0)