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