On the Concatenation of One-Turn Pushdowns

Recently two ways of concatenating pushdowns have be investigated and it has been argued that the resulting storage types might be useful for the description of natural languages. In this paper I will consider concatenations of oneeturn pushdowns. I will give characterizations of the languages accepted by automata using these storage types in terms of linear grammars with controlled derivations. These representations show that for oneeturn pushdowns both ways of concatenating are equivalent. Further a relation to the welllknown hierarchy of Khabbaz is established.