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