-a^{}_{} b^{a2,v0}_{a0,a1} c^{a4,v1}_{c0,a3} eta1^{a3}_{a2} gamma1^{a1}_{a4} a+(c0) a+(a0) a-(v1) a-(v0)
-a^{}_{} b^{a2,v0}_{a0,a1} c^{a4,v1}_{c0,a3} lambda2^{a1,a3}_{a2,a4} a+(c0) a+(a0) a-(v1) a-(v0)
-1/2 a^{}_{} b^{a3,v0}_{a1,a2} c^{a4,v1}_{c0,a0} lambda2^{a1,a2}_{a3,a4} a+(c0) a+(a0) a-(v1) a-(v0)