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