1/2 a^{v2}_{a0} b^{a1}_{v0} c^{c0,c1}_{v1,v2} gamma1^{a0}_{a1} a+(v0) a+(v1) a-(c1) a-(c0)
+1/4 a^{v2}_{a0} b^{a1}_{v2} c^{c0,c1}_{v0,v1} gamma1^{a0}_{a1} a+(v0) a+(v1) a-(c1) a-(c0)