1/4 a^{a0,a1}_{v0,v1} b^{a4,v2}_{a2,a3} c^{}_{} lambda2^{a2,a3}_{a1,a4} a+(v0) a+(v1) a-(v2) a-(a0)
+1/4 a^{a1,a2}_{v0,v1} b^{a0,v2}_{a3,a4} c^{}_{} eta1^{a4}_{a2} eta1^{a3}_{a1} a+(v0) a+(v1) a-(v2) a-(a0)
+1/8 a^{a1,a2}_{v0,v1} b^{a0,v2}_{a3,a4} c^{}_{} lambda2^{a3,a4}_{a1,a2} a+(v0) a+(v1) a-(v2) a-(a0)