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