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