1/2 a^{a0}_{c0} b^{c2,c3}_{c1,c4} c^{c4}_{a1} eta1^{a1}_{a0} a+(c0) a+(c1) a-(c3) a-(c2)
+a^{a0}_{c2} b^{c1,c2}_{c0,c3} c^{c3}_{a1} a+(c0) a+(a1) a-(a0) a-(c1)
-a^{a0}_{c2} b^{c1,c2}_{c0,c3} c^{c3}_{a1} eta1^{a1}_{a0} a+(c0) a-(c1)
+1/4 a^{a0}_{c4} b^{c2,c3}_{c0,c1} c^{c4}_{a1} eta1^{a1}_{a0} a+(c0) a+(c1) a-(c3) a-(c2)
-1/2 a^{a0}_{c4} b^{c2,c4}_{c0,c1} c^{c3}_{a1} eta1^{a1}_{a0} a+(c0) a+(c1) a-(c3) a-(c2)