Linear Context Free Languages

Abstract. In this paper, I present the class of linear context free languages (LCFLs) with a class of non-deterministic one-way two-head (read only) automata, called non-deterministic linear automata (NLA). At the begining of the work of an NLA, the reading heads are installed under the opposite ends of the given input string. Then, each head can move in one direction only, the left head from left to right, while the right head from right to left. I give formal definitions of two non-deterministic versions of the linear automata, without and with ε-transitions, and their corresponding computations. Deterministic linear automata model unambiguous structural analysers, while the class of the languages recognized by them does not coincide with the class of deterministic linear languages recognized by deterministic push-down machines. I compare the linear automata with other models of LCFLs. In particular, I consider a subclass of unambiguous linear context-free languages and define cor...

• Type: Conference
• Year: 2007
• Where: ICTAC
• Authors: Roussanka Loukanova
• Keywords: Deterministic Linear, ICTAC 2007, Linear Automata, Non-deterministic Linear Automata