1/2 a^{c0,a0}_{v0,v1} b^{v2}_{a1} c^{a2}_{v2} gamma1^{a1}_{a2} a+(v0) a+(v1) a-(a0) a-(c0)
+1/2 a^{c0,a1}_{v0,v1} b^{v2}_{a2} c^{a0}_{v2} eta1^{a2}_{a1} a+(v0) a+(v1) a-(a0) a-(c0)