-a^{c0,a1}_{c3,a0} b^{c1,v1}_{a2,v0} c^{c3}_{c2} eta1^{a2}_{a1} a+(c2) a+(a0) a+(v0) a-(v1) a-(c1) a-(c0)
+a^{c0,a1}_{c3,a0} b^{c3,v1}_{a2,v0} c^{c2}_{c1} eta1^{a2}_{a1} a+(c1) a+(a0) a+(v0) a-(v1) a-(c2) a-(c0)