Tree substitution grammars (TSGs) are a compelling alternative to context-free grammars for modelling syntax. However, many popular techniques for estimating weighted TSGs (under the moniker of Data Oriented Parsing) suffer from the problems of inconsistency and over-fitting. We present a theoretically principled model which solves these problems using a Bayesian non-parametric formulation. Our...

Critical Discourse Analysis (CDA) could be seen as a theory in qualitative more than in qualitative stud- ies. This might have led to difficulty in doing CDA. Accordingly, this study attempted to develop a quan- titative profile in the form of an analytic rubric. For this purpose, Fairclough’s model of CDA was select- ed as the research framework. The techniques used for structuring analy...

In this paper, it is argued that Critical Discourse Studies (CDS) should be extended to also include what may be called Critical Context Studies (CCS). After a summary of the new theory of context, defined in terms of special mental models in episodic memory, subjectively representing the ‘definition of the communicative situation’ by the participants, it is argued how a critical analysis of te...

Because of the dispersion of activities in big cities, employing highways as the most important connecting way is indispensable. In today world, highways are connection arteries of cities transporting people to their social activities. Because of continual use of highway, their walls prepare a context for conveying many Social, Cultural, Economic, etc concepts. That is why most economic promoti...

Tree controlled grammars are context-free grammars where the associated language only contains those terminal words which have a derivation where the word of any level of the corresponding derivation tree belongs to a given regular language. We present some results on the power of such grammars where we restrict the regular languages to some known subclasses of the family of regular languages.

We study the compressed word problem: a variant of the word problem for finitely generated groups where the input word is given by a context-free grammar that generates exactly one string. We show that finite extensions and free products preserve the complexity of the compressed word problem. Also, the compressed word problem for a graph group can be solved in polynomial time. These results all...

Let A be a finite, totally ordered alphabet, and let P be the lexicographic ordering on A*. Let X be a subset of A*. The language of minimal words of X is the subset of X composed of the lexicographically minimal word of X for each length: Min(X)=[x # X | \w # X, |w|=|x| O xPw]. The aim of this paper is to prove that if L is a context-free language, then the language Min(L) context-free. ] 1997

In this paper we describe a method of translating a Lambek grammar with one division into an equivalent context-free grammar whose size is bounded by a polynom from the size of the original grammar. Earlier constructions by Buszkowski and Pentus lead to exponential growth of the grammar size. 1 Lambek Grammars and Context-Free Gram-

We prove a Chomsky-Schützenberger representation theorem for weighted multiple context-free languages.