On constacyclic codes over Z(4)[u] / < u(2)-1 > and their Gray images

摘要

We first define a new Gray map from R = Z(4) + uZ(4) to Z(4)(2)where u(2) = 1 and study (1+ 2u)-constacyclic codes over R. Also of interest are some properties of (1 + 2u)-constacyclic codes over R. Considering their Z(4) images, we prove that the Gray images of (1 + 2u)-constacyclic codes of length n over R are cyclic codes of length 2n over Z(4). In many cases the latter codes have better parameters than those in the online database of Aydin and Asamov. We also give a corrected version of a table of new cyclic R-codes published by Ozen et al. [7]. (C) 2016 Elsevier Inc. All rights reserved.