1/2 a^{a3}_{c0,a0,a1} b^{c2}_{c1,a2,a4} eta1^{a4}_{a3} a+(c0) a+(c1) a+(a0) a+(a1) a+(a2) a-(c2)
-1/4 a^{a2}_{c1,a0,a1} b^{c1}_{c0,a3,a4} a+(c0) a+(a0) a+(a1) a+(a3) a+(a4) a-(a2)
+1/2 a^{a3}_{c1,a0,a1} b^{c1}_{c0,a2,a4} eta1^{a4}_{a3} a+(c0) a+(a0) a+(a1) a+(a2)