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