Repeated-root constacyclic codes of prime power lengths over finite chain rings

© 2016 Elsevier Inc. We study the algebraic structure of repeated-root λ-constacyclic codes of prime power length p s over a finite commutative chain ring R with maximal ideal 〈γ〉. It is shown that, for any unit λ of the chain ring R, there always exists an element r∈R such that λ−r p s is not inv...

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Bibliographic Details
Main Authors: Dinh H., Nguyen H., Sriboonchitta S., Vo T.
Format: Journal
Published: 2017
Online Access:https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=84988737040&origin=inward
http://cmuir.cmu.ac.th/jspui/handle/6653943832/41131
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Institution: Chiang Mai University
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Summary:© 2016 Elsevier Inc. We study the algebraic structure of repeated-root λ-constacyclic codes of prime power length p s over a finite commutative chain ring R with maximal ideal 〈γ〉. It is shown that, for any unit λ of the chain ring R, there always exists an element r∈R such that λ−r p s is not invertible, and furthermore, the ambient ring R[x]〈xps−λ〉 is a local ring with maximal ideal 〈x−r,γ〉. When there is a unit λ 0 such that λ=λ 0 p s , the nilpotency index of x−λ 0 in the ambient ring R[x]〈xps−λ〉 is established. When λ=λ 0 p s +γw, for some unit w of R, it is shown that the ambient ring R[x]〈xps−λ〉 is a chain ring with maximal ideal 〈x p s −λ 0 〉, which in turn provides structure and sizes of all λ-constacyclic codes and their duals. Among other things, situations when a linear code over R is both α- and β-constacyclic, for different units α, β, are discussed.