-a^{c0,a1}_{c4,a0} b^{c1}_{v0} c^{c3,c4}_{c2,a2} eta1^{a2}_{a1} a+(c2) a+(a0) a+(v0) a-(c3) a-(c1) a-(c0)
-1/2 a^{c0,a1}_{c4,a0} b^{c4}_{v0} c^{c2,c3}_{c1,a2} eta1^{a2}_{a1} a+(c1) a+(a0) a+(v0) a-(c3) a-(c2) a-(c0)