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