a^{v1,v2}_{a1,v0} b^{a0}_{v2} c^{a2}_{c0} gamma1^{a1}_{a2} a+(c0) a+(v0) a-(v1) a-(a0)
-a^{v1,v2}_{a1,v0} b^{a2}_{v2} c^{a0}_{c0} gamma1^{a1}_{a2} a+(c0) a+(v0) a-(v1) a-(a0)