Regularity of monoids under Schutzenberger products
  In this paper we give a partial answer to the problem which is about the regularity of Schutzenberger products in semigroups asked by Gallagher in his thesis [Problem 6.1.6]{Gallagher} and, also, we investigate the regularity for the new version of the Schutzenberger product which was defined in [Ates]. 
Firat Ates and Ahmet Sinan Cevik