z 6 a 12 + z 4 a 12 − 2 z 2 a 12 − a 12 − z 8 a 10 − 2 z 6 a 10 + z 4 a 10 + z 2 a 10 − 2 a 10 − z 8 a 8 − 2 z 6 a 8 + 2 z 4 a 8 + 6 z 2 a 8 + 4 a 8 + 2 z 6 a 6 + 7 z 4 a 6 + 6 z 2 a 6 {\displaystyle z^{6}a^{12}+z^{4}a^{12}-2z^{2}a^{12}-a^{12}-z^{8}a^{10}-2z^{6}a^{10}+z^{4}a^{10}+z^{2}a^{10}-2a^{10}-z^{8}a^{8}-2z^{6}a^{8}+2z^{4}a^{8}+6z^{2}a^{8}+4a^{8}+2z^{6}a^{6}+7z^{4}a^{6}+6z^{2}a^{6}}
