1/2 a^{c1,c2}_{c0,v0} b^{v1}_{c3} c^{c3}_{v1} a+(c0) a+(v0) a-(c2) a-(c1)
-1/2 a^{c0,c1}_{c3,v0} b^{v1}_{c2} c^{c3}_{v1} a+(c2) a+(v0) a-(c1) a-(c0)