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