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