-1/2 a^{a1,a2}_{c0,a0} b^{c1,v1}_{a3,v0} c^{v2}_{c2} lambda2^{a0,a3}_{a1,a2} a+(c0) a+(c2) a+(v0) a-(v2) a-(v1) a-(c1)
-a^{a1,a2}_{c1,a0} b^{c1,v1}_{a3,v0} c^{v2}_{c0} eta1^{a3}_{a2} a+(c0) a+(a0) a+(v0) a-(v2) a-(v1) a-(a1)
-1/2 a^{a1,a2}_{c1,a0} b^{c1,v1}_{a3,v0} c^{v2}_{c0} lambda2^{a0,a3}_{a1,a2} a+(c0) a+(v0) a-(v2) a-(v1)