a 4 z 8 + 2 a 2 z 8 + z 8 − a 6 z 6 + 5 a 4 z 6 + 10 a 2 z 6 − z 6 a − 2 + 3 z 6 − 5 a 6 z 4 + 10 a 4 z 4 + 17 a 2 z 4 − 3 z 4 a − 2 − 8 a 6 z 2 + 11 a 4 z 2 + 11 a 2 z 2 − 2 z 2 a − 2 − 5 z 2 − 4 a 6 + 5 a 4 + 2 a 2 − 2 {\displaystyle a^{4}z^{8}+2a^{2}z^{8}+z^{8}-a^{6}z^{6}+5a^{4}z^{6}+10a^{2}z^{6}-z^{6}a^{-2}+3z^{6}-5a^{6}z^{4}+10a^{4}z^{4}+17a^{2}z^{4}-3z^{4}a^{-2}-8a^{6}z^{2}+11a^{4}z^{2}+11a^{2}z^{2}-2z^{2}a^{-2}-5z^{2}-4a^{6}+5a^{4}+2a^{2}-2}