− a 4 z 10 + a 6 z 8 − 7 a 4 z 8 + a 2 z 8 + 5 a 6 z 6 − 17 a 4 z 6 + 5 a 2 z 6 + 7 a 6 z 4 − 15 a 4 z 4 + 7 a 2 z 4 + a 6 z 2 + a 4 z 2 + 2 a 2 z 2 − 3 a 6 + 5 a 4 − a 2 {\displaystyle -a^{4}z^{10}+a^{6}z^{8}-7a^{4}z^{8}+a^{2}z^{8}+5a^{6}z^{6}-17a^{4}z^{6}+5a^{2}z^{6}+7a^{6}z^{4}-15a^{4}z^{4}+7a^{2}z^{4}+a^{6}z^{2}+a^{4}z^{2}+2a^{2}z^{2}-3a^{6}+5a^{4}-a^{2}}
