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