a^{a1,a2}_{c0,a0} b^{v0}_{a3} c^{v1}_{a4} eta1^{a4}_{a2} eta1^{a3}_{a1} a+(c0) a+(a0) a-(v1) a-(v0)
+1/2 a^{a1,a2}_{c0,a0} b^{v0}_{a3} c^{v1}_{a4} lambda2^{a3,a4}_{a1,a2} a+(c0) a+(a0) a-(v1) a-(v0)
-1/2 a^{a2,a3}_{c0,a1} b^{v0}_{a0} c^{v1}_{a4} lambda2^{a1,a4}_{a2,a3} a+(c0) a+(a0) a-(v1) a-(v0)
+1/2 a^{a2,a3}_{c0,a1} b^{v0}_{a4} c^{v1}_{a0} lambda2^{a1,a4}_{a2,a3} a+(c0) a+(a0) a-(v1) a-(v0)