1/2 a^{}_{a0,a3} b^{c0,a1,a2,a4}_{} gamma1^{a3}_{a4} a+(a0) a-(a2) a-(a1) a-(c0)
+1/2 a^{}_{a1,a2} b^{c0,a0,a3,a4}_{} gamma1^{a2}_{a4} gamma1^{a1}_{a3} a-(a0) a-(c0)
+1/4 a^{}_{a1,a2} b^{c0,a0,a3,a4}_{} lambda2^{a1,a2}_{a3,a4} a-(a0) a-(c0)