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