1/2 a^{a0,a1}_{c0,c2} b^{c2,a2}_{a3,v0} c^{a4}_{c1} gamma1^{a3}_{a4} a+(c0) a+(c1) a+(v0) a-(a2) a-(a1) a-(a0)
-a^{a0,a3}_{c0,c2} b^{c2,a1}_{a4,v0} c^{a2}_{c1} eta1^{a4}_{a3} a+(c0) a+(c1) a+(v0) a-(a2) a-(a1) a-(a0)