New type i binary [72, 36, 12] self-dual codes from composite matrices and R1 lifts

Abstract

<p style='text-indent:20px;'>In this work, we define three composite matrices derived from group rings. We employ these composite matrices to create generator matrices of the form <inline-formula><tex-math id="M3">\begin{document}$ [I_n \ | \ \Omega(v)], $\end{document}</tex-math></inline-formula> where <inline-formula><tex-math id="M4">\begin{document}$ I_n $\end{document}</tex-math></inline-formula> is the identity matrix and <inline-formula><tex-math id="M5">\begin{document}$ \Omega(v) $\end{document}</tex-math></inline-formula> is a composite matrix and search for binary self-dual codes with parameters <inline-formula><tex-math id="M6">\begin{document}$ [36,18, 6 \ \text{or} \ 8]. $\end{document}</tex-math></inline-formula> We next lift these codes over the ring <inline-formula><tex-math id="M7">\begin{document}$ R_1 = \mathbb{F}_2+u\mathbb{F}_2 $\end{document}</tex-math></inline-formula> to obtain codes whose binary images are self-dual codes with parameters <inline-formula><tex-math id="M8">\begin{document}$ [72,36,12]. $\end{document}</tex-math></inline-formula> Many of these codes turn out to have weight enumerators with parameters that were not known in the literature before. In particular, we find <inline-formula><tex-math id="M9">\begin{document}$ 30 $\end{document}</tex-math></inline-formula> new Type I binary self-dual codes with parameters <inline-formula><tex-math id="M10">\begin{document}$ [72,36,12]. $\end{document}</tex-math></inline-formula></p>