1/4 a^{c0}_{v0} b^{a0,v1}_{c1,c2} c^{c1,c2}_{a1,a2} a+(a1) a+(a2) a+(v0) a-(v1) a-(a0) a-(c0)
-1/2 a^{c0}_{v0} b^{a1,v1}_{c1,c2} c^{c1,c2}_{a0,a2} eta1^{a2}_{a1} a+(a0) a+(v0) a-(v1) a-(c0)
+a^{c0}_{v0} b^{a1,v1}_{c1,c3} c^{c2,c3}_{a0,a2} eta1^{a2}_{a1} a+(c1) a+(a0) a+(v0) a-(v1) a-(c2) a-(c0)