1/4 a^{a0,v2}_{a1,v0} b^{c0,a2}_{v1,v2} c^{c3,c4}_{c1,c2} gamma1^{a1}_{a2} a+(c1) a+(c2) a+(v0) a+(v1) a-(a0) a-(c4) a-(c3) a-(c0)