1/2 a^{c0,v0}_{a0,a1} b^{a3,v1}_{c1,a2} c^{c1}_{a4} eta1^{a4}_{a3} a+(a0) a+(a1) a+(a2) a-(v1) a-(v0) a-(c0)
-a^{c0,v0}_{a0,a3} b^{a4,v1}_{c1,a1} c^{c1}_{a2} gamma1^{a3}_{a4} a+(a0) a+(a1) a+(a2) a-(v1) a-(v0) a-(c0)