Self-orthogonal codes from equitable partitions of distance-regular graphs

Abstract

<p style='text-indent:20px;'>We give two methods for a construction of self-orthogonal linear codes from equitable partitions of distance-regular graphs. By applying these methods, we construct self-orthogonal codes from equitable partitions of the graph of unitals in <inline-formula><tex-math id="M1">\begin{document}$ PG(2,4) $\end{document}</tex-math></inline-formula> and the only known strongly regular graph with parameters <inline-formula><tex-math id="M2">\begin{document}$ (216,40,4,8) $\end{document}</tex-math></inline-formula>. Some of the codes obtained are optimal.</p>