-1/2 a^{v0,v1}_{c0,a0} b^{c0,v2}_{a1,a3} c^{a4}_{a2} gamma1^{a3}_{a4} a+(a0) a+(a1) a+(a2) a-(v2) a-(v1) a-(v0)
-1/4 a^{v0,v1}_{c0,a3} b^{c0,v2}_{a0,a1} c^{a4}_{a2} gamma1^{a3}_{a4} a+(a0) a+(a1) a+(a2) a-(v2) a-(v1) a-(v0)