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