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