1/2 a^{v0}_{a2} b^{c1,a0}_{c0,v0} c^{a1,a3}_{c2,c3} gamma1^{a2}_{a3} a+(c0) a+(c2) a+(c3) a-(a1) a-(a0) a-(c1)
+1/4 a^{v0}_{a2} b^{c1,a3}_{c0,v0} c^{a0,a1}_{c2,c3} gamma1^{a2}_{a3} a+(c0) a+(c2) a+(c3) a-(a1) a-(a0) a-(c1)