− z 6 + a 2 z 4 + z 4 a 2 − 3 z 4 + a 2 z 2 + z 2 a 2 − z 2 − a 2 − 1 a 2 + 3 {\displaystyle -z^{6}+a^{2}z^{4}+{\frac {z^{4}}{a^{2}}}-3z^{4}+a^{2}z^{2}+{\frac {z^{2}}{a^{2}}}-z^{2}-a^{2}-{\frac {1}{a^{2}}}+3}
