Repeated-root constacyclic codes of length klapb over a finite field

In this paper, we give an sufficient and necessary condition that a polynomial is irreducible over FqFq. For different odd primes k, l and p  , we obtain generator polynomials of constacyclic codes of length klapbklapb over finite field FqFq, where charFq=pcharFq=p and (ordkq,l)=1(ordkq,l)=1. And we answer the question in [3] under the condition.