On non-full-rank perfect codes over finite fields

TL;DR

This paper investigates the structure of non-full-rank perfect codes over finite fields, characterizes their orthogonal codes, and constructs specific ternary 1-perfect codes with particular parameters.

Contribution

It provides necessary and sufficient conditions for non-full-rank $q$-ary 1-perfect codes and generalizes the concatenation construction to the $q$-ary case.

Findings

Orthogonal code to non-full-rank perfect code is a constant-weight code.

Necessary and sufficient conditions for non-full-rank perfect codes are established.

Constructed ternary 1-perfect codes of length 13 and rank 12.

Abstract

The paper deals with the perfect 1-error correcting codes over a finite field with $q$ elements (briefly $q$-ary 1-perfect codes). We show that the orthogonal code to the $q$-ary non-full-rank 1-perfect code of length $n = (q^{m}-1)/(q-1)$ is a $q$-ary constant-weight code with Hamming weight equals to $q^{m - 1}$ where $m$ is any natural number not less than two. We derive necessary and sufficient conditions for $q$-ary 1-perfect codes of non-full rank. We suggest a generalization of the concatenation construction to the $q$-ary case and construct the ternary 1-perfect codes of length 13 and rank 12.