1/4 a^{a0,a1,a2,a3}_{} b^{}_{a4,a5,v0} eta1^{a5}_{a3} eta1^{a4}_{a2} a+(v0) a-(a1) a-(a0)
+1/8 a^{a0,a1,a2,a3}_{} b^{}_{a4,a5,v0} lambda2^{a4,a5}_{a2,a3} a+(v0) a-(a1) a-(a0)
+1/6 a^{a0,a1,a2,a4}_{} b^{}_{a3,a5,v0} eta1^{a5}_{a4} a+(a3) a+(v0) a-(a2) a-(a1) a-(a0)