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