-1/4 a^{v1}_{v0} b^{c0,a0}_{v2,v3} c^{c1,a3}_{a1,a2} lambda2^{a1,a2}_{a0,a3} a+(v0) a+(v2) a+(v3) a-(v1) a-(c1) a-(c0)
+1/2 a^{v2}_{v0} b^{c0,a0}_{v1,v2} c^{c1,a3}_{a1,a2} lambda2^{a1,a2}_{a0,a3} a+(v0) a+(v1) a-(c1) a-(c0)
+a^{v2}_{v0} b^{c0,a2}_{v1,v2} c^{c1,a1}_{a0,a3} eta1^{a3}_{a2} a+(a0) a+(v0) a+(v1) a-(a1) a-(c1) a-(c0)