-1/12 a^{a2,v0}_{a0,a1} b^{}_{a3,a4,a5,v0} a+(a0) a+(a1) a+(a3) a+(a4) a+(a5) a-(a2)
+1/4 a^{a4,v0}_{a0,a1} b^{}_{a2,a3,a5,v0} eta1^{a5}_{a4} a+(a0) a+(a1) a+(a2) a+(a3)
-1/4 a^{a4,v0}_{a0,a1} b^{}_{a2,a3,a5,v1} eta1^{a5}_{a4} a+(a0) a+(a1) a+(a2) a+(a3) a+(v1) a-(v0)