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