-1/2 a^{c1,a0}_{c0,c2} b^{c2}_{a2} c^{a1,a3}_{v0,v1} gamma1^{a2}_{a3} a+(c0) a+(v0) a+(v1) a-(a1) a-(a0) a-(c1)
+1/4 a^{c1,a2}_{c0,c2} b^{c2}_{a3} c^{a0,a1}_{v0,v1} eta1^{a3}_{a2} a+(c0) a+(v0) a+(v1) a-(a1) a-(a0) a-(c1)