1/4 a^{a1,a2}_{a0} b^{}_{a3,a4,v0,v1} eta1^{a4}_{a2} eta1^{a3}_{a1} a+(a0) a+(v0) a+(v1)
+1/8 a^{a1,a2}_{a0} b^{}_{a3,a4,v0,v1} lambda2^{a3,a4}_{a1,a2} a+(a0) a+(v0) a+(v1)
-1/2 a^{a1,a3}_{a0} b^{}_{a2,a4,v0,v1} eta1^{a4}_{a3} a+(a0) a+(a2) a+(v0) a+(v1) a-(a1)
-1/4 a^{a2,a3}_{a1} b^{}_{a0,a4,v0,v1} lambda2^{a1,a4}_{a2,a3} a+(a0) a+(v0) a+(v1)