1/4 a^{c0,c1,a0,a1}_{} b^{}_{c2,a2,a3,v0} eta1^{a3}_{a1} eta1^{a2}_{a0} a+(c2) a+(v0) a-(c1) a-(c0)
+1/8 a^{c0,c1,a0,a1}_{} b^{}_{c2,a2,a3,v0} lambda2^{a2,a3}_{a0,a1} a+(c2) a+(v0) a-(c1) a-(c0)
+1/2 a^{c0,c1,a0,a2}_{} b^{}_{c2,a1,a3,v0} eta1^{a3}_{a2} a+(c2) a+(a1) a+(v0) a-(a0) a-(c1) a-(c0)