-1/4 a^{a1,a2}_{c0,a0} b^{c2,c3}_{c1,a3} c^{v1}_{v0} lambda2^{a0,a3}_{a1,a2} a+(c0) a+(c1) a+(v0) a-(v1) a-(c3) a-(c2)
-a^{a1,a2}_{c2,a0} b^{c1,c2}_{c0,a3} c^{v1}_{v0} eta1^{a3}_{a2} a+(c0) a+(a0) a+(v0) a-(v1) a-(a1) a-(c1)
+1/2 a^{a1,a2}_{c2,a0} b^{c1,c2}_{c0,a3} c^{v1}_{v0} lambda2^{a0,a3}_{a1,a2} a+(c0) a+(v0) a-(v1) a-(c1)