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