-a^{c0,a3}_{c3,a0} b^{c1}_{a1} c^{c2,c3}_{a2,a4} eta1^{a4}_{a3} a+(a0) a+(a1) a+(a2) a-(c2) a-(c1) a-(c0)
-1/2 a^{c0,a3}_{c3,a0} b^{c3}_{a1} c^{c1,c2}_{a2,a4} eta1^{a4}_{a3} a+(a0) a+(a1) a+(a2) a-(c2) a-(c1) a-(c0)
-1/2 a^{c0,a3}_{c3,a0} b^{c1}_{a4} c^{c2,c3}_{a1,a2} eta1^{a4}_{a3} a+(a0) a+(a1) a+(a2) a-(c2) a-(c1) a-(c0)
-1/4 a^{c0,a3}_{c3,a0} b^{c3}_{a4} c^{c1,c2}_{a1,a2} eta1^{a4}_{a3} a+(a0) a+(a1) a+(a2) a-(c2) a-(c1) a-(c0)