1/2 a^{a1}_{v0} b^{v1}_{a0} c^{a4,v2}_{a2,a3} lambda2^{a2,a3}_{a1,a4} a+(a0) a+(v0) a-(v2) a-(v1)
-a^{a1}_{v0} b^{v1}_{a2} c^{a4,v2}_{a0,a3} eta1^{a3}_{a1} gamma1^{a2}_{a4} a+(a0) a+(v0) a-(v2) a-(v1)
-a^{a1}_{v0} b^{v1}_{a2} c^{a4,v2}_{a0,a3} lambda2^{a2,a3}_{a1,a4} a+(a0) a+(v0) a-(v2) a-(v1)