1/4 a^{a0,a1}_{} b^{}_{a2,a3,v0,v1} eta1^{a3}_{a1} eta1^{a2}_{a0} a+(v0) a+(v1)
+1/8 a^{a0,a1}_{} b^{}_{a2,a3,v0,v1} lambda2^{a2,a3}_{a0,a1} a+(v0) a+(v1)
-1/2 a^{a0,a2}_{} b^{}_{a1,a3,v0,v1} eta1^{a3}_{a2} a+(a1) a+(v0) a+(v1) a-(a0)