-a^{c0,a0}_{c3,v0} b^{c1}_{a1} c^{c3}_{c2} eta1^{a1}_{a0} a+(c2) a+(v0) a-(c1) a-(c0)
+a^{c0,a0}_{c3,v0} b^{c3}_{a1} c^{c2}_{c1} eta1^{a1}_{a0} a+(c1) a+(v0) a-(c2) a-(c0)