Statistical Parsing with Context-Free Filtering Grammar Michael Demko Master of Science Graduate Department of Computer Science University of Toronto 2007 Statistical parsers that simultaneously generate both phrase-structure and lexical dependency trees have been limited in two important ways: the detection of non-projective dependencies has not been integrated with other parsing decisions, or...

We present a novel approach for finding discontinuities that outperforms previously published results on this task. Rather than using a deeper grammar formalism, our system combines a simple unlexicalized PCFG parser with a shallow pre-processor. This pre-processor, which we call a trace tagger, does surprisingly well on detecting where discontinuities can occur without using phase structure in...

We give a language of unique geodesic normal forms for the BaumslagSolitar group BS(1, 2) that is context-free and 1-counter. We discuss the classes of context-free, 1-counter and counter languages, and explain how they are inter-related.

Incremental sentence generation imposes special constraints on the representation of the grammar and the design of the formulator (the module which is responsible for constructing the syntactic and morphological structure). In the model of natural speech production presented here, a formalism called Segment Grammar is used for the representation of linguistic knowledge. We give a definition of ...

In [4] Berstel and Sakarovitch pointed out that from a proof given in [2] one can deduce that a rational set of a group G which is included in a subgroup H of G is already rational in H (an explicit proof is given in [12]). They called this “a kind of Fatou property of groups” according to similar properties of certain formal power series [14]. Another kind of Fatou property was shown by Eilenb...

In its most general form, the problem of inferring the intentions of a mobile user from his or her spatial behavior is equivalent to the plan recognition problem which is known to be intractable. Tractable special cases of the problem are therefore of great practical interest. Using formal grammars, intention recognition problems can be stated as parsing problems in a way that makes the connect...

We continue the investigation of the power of the computability models introduced in 10] under the name of transition super-cell systems. We compare these systems with classic mechanisms in formal language theory, context-free and matrix grammars, E0L and ET0L systems, interpreted as generating mechanisms of number relations (we take the Parikh image of the usual language generated by these mec...

The complexity of formal languages which are generated by S-unimodal systems on interval covers is studied. It is shown that there exist S-unimodal systems with nonrecursive languages, those with recursive but not context-sensitive languages, and those with context-sensitive but not regular languages. It is also shown that S-unimodal systems with regular languages include all systems with finit...

The word problem of a group G = Σ can be defined as the set of formal words in Σ * that represent the identity in G. When viewed as formal languages, this gives a strong connection between classes of groups and classes of formal languages. For example, Anisimov [An¯ ı71] showed that a group is finite if and only if its word problem is a regular language, and Muller and Schupp [MS83] showed that...

Finding computationally valuable representations of models of predicate logic formulas is an important subtask in many elds related to automated theorem proving, e.g. automated model building or semantic resolution. In this article we investigate the use of context-free languages for representing single Herbrand models, which appear to be a natural extension of \linear atomic representations" a...