1/2 a^{a1,a2}_{a0} b^{c0,c1}_{a3,v0} eta1^{a3}_{a2} a+(a0) a+(v0) a-(a1) a-(c1) a-(c0)
+1/4 a^{a1,a2}_{a0} b^{c0,c1}_{a3,v0} lambda2^{a0,a3}_{a1,a2} a+(v0) a-(c1) a-(c0)