-1/2 a^{v1}_{v0} b^{a1,a2}_{a0,v2} c^{v3}_{a3} lambda2^{a0,a3}_{a1,a2} a+(v0) a+(v2) a-(v3) a-(v1)
+a^{v2}_{v0} b^{a1,a2}_{a0,v2} c^{v1}_{a3} eta1^{a3}_{a2} a+(a0) a+(v0) a-(v1) a-(a1)
-1/2 a^{v2}_{v0} b^{a1,a2}_{a0,v2} c^{v1}_{a3} lambda2^{a0,a3}_{a1,a2} a+(v0) a-(v1)