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