Some operators that preserve the locality of a pseudovariety of   semigroups
  It is shown that if V is a local monoidal pseudovariety of semigroups, then K(m)V, D(m)V and LI(m)V are local. Other operators of the form Z(m)(_) are considered. In the process, results about the interplay between operators Z(m)(_) and (_)*D_k are obtained. 
Alfredo Costa and Ana Escada
math.GR