a 7 z 3 − a 7 z + 2 a 6 z 4 − 2 a 6 z 2 + a 6 + 2 a 5 z 5 − a 5 z 3 + a 4 z 6 + 2 a 4 z 4 − 4 a 4 z 2 + 2 a 4 + 4 a 3 z 5 − 6 a 3 z 3 + 2 a 3 z + a 2 z 6 + a 2 z 4 − 4 a 2 z 2 + a 2 + 2 a z 5 − 4 a z 3 + a z + z 4 − 2 z 2 + 1 {\displaystyle a^{7}z^{3}-a^{7}z+2a^{6}z^{4}-2a^{6}z^{2}+a^{6}+2a^{5}z^{5}-a^{5}z^{3}+a^{4}z^{6}+2a^{4}z^{4}-4a^{4}z^{2}+2a^{4}+4a^{3}z^{5}-6a^{3}z^{3}+2a^{3}z+a^{2}z^{6}+a^{2}z^{4}-4a^{2}z^{2}+a^{2}+2az^{5}-4az^{3}+az+z^{4}-2z^{2}+1}
