Skew generalized quasi-cyclic codes over non-chain ring $F_q+vF_q$
Kundan Suxena, Indibar Debnath, Om Prakash
TL;DR
This work extends skew generalized quasi-cyclic codes to the non-chain ring $S = F_q + vF_q$ with $v^2 = v$ under a Galois automorphism $\theta_t$, developing a comprehensive algebraic framework for SGQC codes over $S$. By representing codes as left $S[x;\theta_t]$-submodules of a product ring and relating them to constituent SGQC codes over $F_q$ via the map $\mu$, the authors establish duality, self-duality criteria, and a robust generator theory that includes $1$-generator and $\rho$-generator polynomials, parity-check polynomials, and dimension bounds. They prove the dual of an SGQC code is SGQC and that self-duality reduces to self-duality of the constituent codes, while providing idempotent generators under coprimality conditions and practical $\rho$-generator constructions, along with MAGMA-based examples and BCH-type distance bounds. The results equip code designers with explicit construction tools over $S$ and indicate potential for improved parameters and quantum-code applications.
Abstract
For a prime $p$, let $F_q$ be the finite field of order $q= p^d$. This paper presents the study on skew generalized quasi-cyclic (SGQC) codes of length $n$ over the non-chain ring $F_q+vF_q$ where $v^2=v$ and $θ_t$ is the Galois automorphism. Here, first, we prove the dual of an SGQC code of length $n$ is also an SGQC code of the same length and derive a necessary and sufficient condition for the existence of a self-dual SGQC code. Then, we discuss the $1$-generator polynomial and the $ρ$-generator polynomial for skew generalized quasi-cyclic codes. Further, we determine the dimension and BCH type bound for the 1-generator skew generalized quasi-cyclic codes. As a by-product, with the help of MAGMA software, we provide a few examples of SGQC codes and obtain some $2$-generator SGQC codes of index $2$.
