1/4 a^{}_{} b^{a0,a1}_{v0,v1} c^{c0,a4}_{a2,a3} lambda2^{a2,a3}_{a1,a4} a+(v0) a+(v1) a-(a0) a-(c0)
+1/4 a^{}_{} b^{a1,a2}_{v0,v1} c^{c0,a0}_{a3,a4} eta1^{a4}_{a2} eta1^{a3}_{a1} a+(v0) a+(v1) a-(a0) a-(c0)
+1/8 a^{}_{} b^{a1,a2}_{v0,v1} c^{c0,a0}_{a3,a4} lambda2^{a3,a4}_{a1,a2} a+(v0) a+(v1) a-(a0) a-(c0)