Abstract
We introduce the finite ring F? + u?F? + u?F?, u? ² = u? , u? ² = 0 , u?.u? = u?.u? = 0 which is not a finite chain ring. We focus on (1 + u?) -constacyclic codes over F? + u?F? + u?F? of odd length. We prove that the Gray image of a linear (1 + u?) -constacyclic code over F? + u?F? + u?F? of odd length n is a quasi-cyclic code of index 4 and length 4n over F?.