1/4 a^{}_{} b^{v1,v2}_{a0,v0} c^{a1,a2}_{v1,v2} a+(a0) a+(v0) a-(a2) a-(a1)
-1/2 a^{}_{} b^{v1,v2}_{a1,v0} c^{a0,a2}_{v1,v2} gamma1^{a1}_{a2} a+(v0) a-(a0)
+a^{}_{} b^{v1,v3}_{a1,v0} c^{a0,a2}_{v2,v3} gamma1^{a1}_{a2} a+(v0) a+(v2) a-(v1) a-(a0)