1/2 a^{a0,a1}_{c0,c2} b^{c2}_{a2} c^{a3,v1}_{c1,v0} gamma1^{a2}_{a3} a+(c0) a+(c1) a+(v0) a-(v1) a-(a1) a-(a0)
+a^{a0,a2}_{c0,c2} b^{c2}_{a3} c^{a1,v1}_{c1,v0} eta1^{a3}_{a2} a+(c0) a+(c1) a+(v0) a-(v1) a-(a1) a-(a0)