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