Classes of Tree Languages and DR Tree Languages Given by Classes of Semigroups
Ferenc Gécseg · Acta Cybernetica · 2011
In the first section of the paper we give general conditions under which a class of recognizable tree languages with a given property can be defined by a class of monoids or semigroups defining the class of string languages having the same property. In the second part similar questions are studied for classes of (DR) tree languages recognized by deterministic root-to-frontier tree recognizers.