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