1/4 a^{v0,v1}_{a0,a1} b^{c0,c1}_{a2,v1} c^{a3}_{c2} gamma1^{a2}_{a3} a+(c2) a+(a0) a+(a1) a-(v0) a-(c1) a-(c0)
-1/2 a^{v0,v1}_{a0,a2} b^{c0,c1}_{a1,v1} c^{a3}_{c2} gamma1^{a2}_{a3} a+(c2) a+(a0) a+(a1) a-(v0) a-(c1) a-(c0)