-1/4 a^{a1,a2}_{a0,a3} b^{a4,v1,v2}_{v0} gamma1^{a3}_{a4} a+(a0) a+(v0) a-(v2) a-(v1) a-(a2) a-(a1)
+1/4 a^{a0,a3}_{a1,a2} b^{a4,v1,v2}_{v0} lambda2^{a1,a2}_{a3,a4} a+(v0) a-(v2) a-(v1) a-(a0)