1/4 a^{}_{} b^{a0,a1}_{c0,c1} c^{a4,v0}_{a2,a3} lambda2^{a2,a3}_{a1,a4} a+(c0) a+(c1) a-(v0) a-(a0)
+1/4 a^{}_{} b^{a1,a2}_{c0,c1} c^{a0,v0}_{a3,a4} eta1^{a4}_{a2} eta1^{a3}_{a1} a+(c0) a+(c1) a-(v0) a-(a0)
+1/8 a^{}_{} b^{a1,a2}_{c0,c1} c^{a0,v0}_{a3,a4} lambda2^{a3,a4}_{a1,a2} a+(c0) a+(c1) a-(v0) a-(a0)