Core Concepts
The paper establishes improved upper bounds on the number of non-zero weights of simple-root constacyclic codes by calculating the number of orbits of a larger subgroup of the automorphism group of the code.
Abstract
The paper focuses on establishing improved upper bounds on the number of non-zero weights of simple-root constacyclic codes over finite fields.
Key highlights:
The authors choose a larger subgroup G'' of the automorphism group Aut(C) of the constacyclic code C, which contains the subgroup G' used in previous work.
By calculating the number of G''-orbits of C{0}, the authors derive an explicit upper bound on the number of non-zero weights of C that is strictly smaller than the previous upper bounds.
The results generalize and improve upon the main results in prior work, removing certain constraints and providing a new method to construct few-weight constacyclic codes.
For two special classes of constacyclic codes, the authors obtain even smaller upper bounds by replacing G'' with larger subgroups of the automorphism groups.
Several examples are presented to demonstrate that the new upper bounds are tight and better than the previous ones.