-1/2 a^{a0,v1}_{v0} b^{a3}_{a1,a2} lambda2^{a1,a2}_{a0,a3} a+(v0) a-(v1)
-a^{a2,v1}_{v0} b^{a1}_{a0,a3} eta1^{a3}_{a2} a+(a0) a+(v0) a-(v1) a-(a1)