All α plus μβ-constacyclic codes of length nps over Fpm + uFpm

Let F-p(m) be a finite field with cardinality p(m) and R = F-p(m) + uF(p)(m) with u(2) = 0. We aim to determine all alpha+mu beta-constacyclic codes of length np(s) over R, where alpha, beta is an element of F*(m)(p), n, s is an element of N+ and gcd(n, p) = 1. Let alpha(0) is an element of F*(m)(p) and alpha(ps)(0) = alpha. The residue ring R[x]/< x(nps)- alpha- mu beta > is a chain ring with the maximal ideal (x(n) - alpha(0)) in the case that x(n) - alpha(0) is irreducible in F-p(m) [x]. If x(n) - alpha(0) is reducible in F-p(m) [x], we give the explicit expressions of the ideals of R[x]/< x(nPs) - alpha - mu beta >. Besides, the number of codewords and the dual code of every alpha + mu beta-constacyclic code are provided. (C) 2017 Elsevier Inc. All rights reserved.