a 12 − 3 z 2 a 10 − 3 a 10 + 2 z 4 a 8 + 3 z 2 a 8 + a 8 + 2 z 4 a 6 + 3 z 2 a 6 + a 6 + z 4 a 4 + 2 z 2 a 4 + a 4 {\displaystyle a^{12}-3z^{2}a^{10}-3a^{10}+2z^{4}a^{8}+3z^{2}a^{8}+a^{8}+2z^{4}a^{6}+3z^{2}a^{6}+a^{6}+z^{4}a^{4}+2z^{2}a^{4}+a^{4}}
