Data:L8a20/HOMFLYPT Polynomial

Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle a^4+ a^{-4} -2 a^2 z^2+a^2 z^{-2} -2 z^2 a^{-2} + a^{-2} z^{-2} +z^4-2 z^{-2} -2}