-1/2 a^{v2}_{a0} b^{a2}_{v2} c^{v0,v1}_{a1,a3} eta1^{a3}_{a2} a+(a0) a+(a1) a-(v1) a-(v0)
+1/4 a^{v2}_{a2} b^{a3}_{v2} c^{v0,v1}_{a0,a1} gamma1^{a2}_{a3} a+(a0) a+(a1) a-(v1) a-(v0)