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