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