1/2 a^{a1,a2}_{c2,a0} b^{c0}_{c3} c^{c2,c3}_{c1,v0} a+(c1) a+(a0) a+(v0) a-(a2) a-(a1) a-(c0)
-1/2 a^{a1,a2}_{c2,a0} b^{c2}_{c3} c^{c1,c3}_{c0,v0} a+(c0) a+(a0) a+(v0) a-(a2) a-(a1) a-(c1)