-1/2 a^{a0,a1}_{c0,v0} b^{c0}_{a2} c^{a3}_{v1} gamma1^{a2}_{a3} a+(v0) a+(v1) a-(a1) a-(a0)
-a^{a0,a2}_{c0,v0} b^{c0}_{a3} c^{a1}_{v1} eta1^{a3}_{a2} a+(v0) a+(v1) a-(a1) a-(a0)