a^{a1}_{a0} b^{}_{} c^{a3,v1}_{a2,v0} eta1^{a2}_{a1} gamma1^{a0}_{a3} a+(v0) a-(v1)
+a^{a1}_{a0} b^{}_{} c^{a3,v1}_{a2,v0} lambda2^{a0,a2}_{a1,a3} a+(v0) a-(v1)