-a^{c1,a0}_{c0,c3} b^{c3,a2}_{c2,v0} c^{a1}_{a3} eta1^{a3}_{a2} a+(c0) a+(c2) a+(v0) a-(a1) a-(a0) a-(c1)
+a^{c1,a2}_{c0,c3} b^{c3,a0}_{c2,v0} c^{a1}_{a3} eta1^{a3}_{a2} a+(c0) a+(c2) a+(v0) a-(a1) a-(a0) a-(c1)