z 7 a 11 − 6 z 5 a 11 + 10 z 3 a 11 − 4 z a 11 + z 8 a 10 − 6 z 6 a 10 + 11 z 4 a 10 − 7 z 2 a 10 + a 10 + 2 z 7 a 9 − 10 z 5 a 9 + 13 z 3 a 9 − 4 z a 9 + z 8 a 8 − 5 z 6 a 8 + 8 z 4 a 8 − 6 z 2 a 8 + a 8 + z 7 a 7 − 3 z 5 a 7 + z 3 a 7 + z 6 a 6 − 2 z 4 a 6 + z 5 a 5 − z 3 a 5 + z 4 a 4 + z 3 a 3 + z 2 a 2 − a 2 {\displaystyle z^{7}a^{11}-6z^{5}a^{11}+10z^{3}a^{11}-4za^{11}+z^{8}a^{10}-6z^{6}a^{10}+11z^{4}a^{10}-7z^{2}a^{10}+a^{10}+2z^{7}a^{9}-10z^{5}a^{9}+13z^{3}a^{9}-4za^{9}+z^{8}a^{8}-5z^{6}a^{8}+8z^{4}a^{8}-6z^{2}a^{8}+a^{8}+z^{7}a^{7}-3z^{5}a^{7}+z^{3}a^{7}+z^{6}a^{6}-2z^{4}a^{6}+z^{5}a^{5}-z^{3}a^{5}+z^{4}a^{4}+z^{3}a^{3}+z^{2}a^{2}-a^{2}}