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