Some constacyclic self-dual codes over the integers modulo m2

In this paper, we explore constacyclic self-dual codes over Zm2. We first characterize constacyclic self-dual codes over Zpm of any length. Then we determine the structure of η-constacyclic self-dual codes over Zt2, where η=−1 or −1+2t−1. This structure is used to find some constacyclic self-dual codes over Zm2.