Embedding in factorisable restriction monoids
  Each restriction semigroup is proved to be embeddable in a factorisable restriction monoid, or, equivalently, in an almost factorisable restriction semigroup. It is also established that each restriction semigroup has a proper cover which is embeddable in a semidirect product of a semilattice by a group. 
Victoria Gould, Miklos Hartmann and Maria Szendrei
math.RA