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