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