1/2 a^{a0}_{c2} b^{a1}_{a2} c^{c2,a3}_{c0,c1} gamma1^{a2}_{a3} a+(c0) a+(c1) a-(a1) a-(a0)
-1/2 a^{a2}_{c2} b^{a0}_{a3} c^{c2,a1}_{c0,c1} eta1^{a3}_{a2} a+(c0) a+(c1) a-(a1) a-(a0)