-1/2 a^{a0}_{v0} b^{v2,v3}_{a1,v1} c^{a3}_{a2} eta1^{a2}_{a0} gamma1^{a1}_{a3} a+(v0) a+(v1) a-(v3) a-(v2)
-1/2 a^{a0}_{v0} b^{v2,v3}_{a1,v1} c^{a3}_{a2} lambda2^{a1,a2}_{a0,a3} a+(v0) a+(v1) a-(v3) a-(v2)