Showing papers on "Formal grammar published in 1997"

Optimality: From Neural Networks to Universal Grammar

Abstract: Can concepts from the theory of neural computation contribute to formal theories of the mind? Recent research has explored the implications of one principle of neural computation, optimization, for the theory of grammar Optimization over symbolic linguistic structures provides the core of a new grammatical architecture, optimality theory The proposition that grammaticality equals optimality sheds light on a wide range of phenomena, from the gulf between production and comprehension in child language, to language learnability, to the fundamental questions of linguistic theory: What is it that the grammars of all languages share, and how may they differ?

Semirings and formal power series: their relevance to formal languages and automata

Abstract: The purpose of Chapter 9 is to develop some classical results on formal languages and automata by an algebraic treatment using semirings, formal power series and matrices. The use of semirings, formal power series and matrices makes the proofs computational in nature and, consequently, more satisfactory from the mathematical point of view than the customary proofs.

Chapter 2 – Categorial Type Logics

Abstract: Publisher Summary This chapter describes the framework of categorial type logic—that is, grammar architecture that can be seen as the logical development of the categorial approach to natural language analysis initiated in the 1930s. For the reader with a background in linguistics, it tries to provide a useful compendium of the logical tools and results one needs to appreciate the categorial research. The reader with a logic background is justified in classifying the grammar formalism discussed in the chapter under the rubric applied logic. In organizing the material, one can opt for a “historical” mode of development or for a state-of-the-art presentation of the internal dynamics of the field. The chapter presents an interpretation of the categorial formalism in terms of structural composition of grammatical resources. The central objective of the type-logical approach is to develop a uniform deductive account of the composition of form and meaning in natural language: formal grammar is presented as logic—a system for reasoning about structured linguistic resources.

Abstraction processes in artificial grammar learning

Abstract: Four experiments explored the extent to which abstract knowledge may underlie subjects' performance when asked to judge the grammaticality of letter strings generated from an artificial grammar. In Experiments 1 and 2 subjects studied grammatical strings instantiated with one set of letters and were then tested on grammatical and ungrammatical strings formed either from the same or a changedletter-set.Evenwith a change ofletter-set, subjects were found to be sensitive to a variety of violations of the grammar. In Experiments 3 and 4, the critical manipulation involved the way in which the training strings were studied: an incidental learning procedure was used for some subjects, and others engaged in an explicit code-breaking task to try to learn the rules of the grammar. When strings were generated from a biconditional (Experiment 4) but not from a standard finite-state grammar (Experiment 3), grammaticality judgements for test strings were independent of their surface similarity to specific studied stri...

Grammars with controlled derivations

Abstract: In [13], N. Chomsky says that “the main problem of immediate relevance to the theory of language is that of determining where in the hierarchy of devices the grammars of natural languages lie.” Formulated in other terms, the question is “where are the natural languages placed in the Chomsky hierarchy?” The debate started in 1959 and is not yet settled. Various arguments over English [4], Mohawk [92], Swiss German [112], Bambara [16], Chinese [95], etc., were given, refuted, rehabilitated — see pro and con arguments as well as further bibliographical information in [38] and [70]. The main difficulty is not a mathematical one but a linguistic one: what is English, what is a natural language, can we separate the syntax and the morphology from semantics or pragmatics? Whatever is or will be the position with respect to these questions, the linguists seem to agree (see again [70]) that “all” natural languages contain constructions which cannot be described by context-free grammars. Three basic such features of natural languages are: reduplication, leading to languages of the form {xx | x ∈ V*} multiple agreements, modeled by languages of the form {a n b n c n | n ≥ 1}, {a n b n c n d n | n ≥ 1}, etc. crossed agreements, as modeled by {a n b m c n d m | n, m ≥ 1}.

A collection of tools for making automata theory and formal languages come alive

Abstract: We present a collection of new and enhanced tools for experimenting with concepts in formal languages and automata theory. New tools, written in Java, include JFLAP for creating and simulating finite automata, pushdown automata and Turing machines; Pâte for parsing restricted and unrestricted grammars and transforming context-free grammars to Chomsky Normal Form; and PumpLemma for proving specific languages are not regular. Enhancements to previous tools LLparse and LRparse, instructional tools for parsing LL(1) and LR(1) grammars, include parsing LL(2) grammars, displaying parse trees, and parsing any context-free grammar with conflict resolution.

A formal model for simple narratives

Abstract: We present a declarative, generative model of simple narratives. Our model contributes to automation of natural language processing because it provides a model of the relationship between surface text and its meaning. This work surpasses previous story modeling work in three important ways. First, we build on developments in commonsense knowledge representation to construct precise formal definitions of components of simple narratives and relations among these components. Second, we develop a new theory of rational intention in autonomous agents to formalize the relation of a character's mental state to actions it undertakes in a narrative. Third, we implement this model in the first story generation system to use a formal grammar for stories. The centerpiece of our model is a story grammar expressing characteristics of event sequences which, when reported in natural language, constitute a narrative. This grammar draws on a separate theory of rational intention in autonomous agents. The grammar makes use of interchangeable world models specifying characters that may appear in a story, emotions they feel, actions they take, and events that happen in narratives. We implement our model in a story generation system which simultaneously generates text and meaning representations. This system represents a significant achievement since it is the first such system constructed from an explicit, formal model for stories. The implementation serves as a concrete demonstration of the computational viability of our model. By generating both semantic representations and the corresponding surface text, our system provides a criterion of correct understanding since surface texts are paired with corresponding internal representations. Our theory of rational intention supports reasoning about the successes and failures of intentional actions and the ramifications of these outcomes. Also, this theory captures relative goals, deadline goals, and recurring goals. Previous theories of intention did not adequately handle as broad a class of goals. Finally, our theory of intention supports the conclusion that an agent which adopts a goal will commit to actions in pursuit of that goal. In addition to its application to narrative understanding, our theory of rational intention is applicable to multi-agent planning and speech-act processing.

Empirical issues in formal syntax and semantics : selected papers from the Colloque de syntaxe et de sémantique de Paris (CSSP 1995)

Abstract: The first Colloquium in Syntax and Semantics in Paris (CSSP 95) was held Oct. 1995 and was organized by members of a research group in formal linguistics belonging to the CNRS.

Autonomous linguistic systems in the language of young children.

Abstract: This paper considers cross-linguistic findings concerning the early development of formal, arbitrary, grammatical systems in normal hearing and deaf children and in children with congenital brain abnormalities. The paper reviews evidence showing an early acquisition of grammatical forms. Such learning is typically dissociated from the development of the relevant semantics. Form-function correspondences were not required for the development of morphological paradigms and for certain aspects of formal syntax. This finding held across all the populations studied. It is hypothesized that the autonomous nature of these formal paradigms accounts for their priority in learning cross-linguistically.

Two-dimensional filters for structured text

Abstract: The paper introduces a method for defining filters for structured text. In the method, the text structure is originally defined by a grammar consisting of a set of productions. To describe the information interests, a two-dimensional template is first created interactively from the grammar to show the structure of a set of textual elements, at a chosen level of detail. The template depicts the hierarchical structure of the elements and indicates also optionality, alternatives, and iteration in the structure. Then, the template is filled by constraints and annotations. The constraints allow giving conditions to the content of parts, to the position of parts in an ordered set of parts, and to the number of parts obeying a specified property. In a compound filter, several templates are connected by annotations. The method is intended to be used as a theoretical framework for developing flexible and powerful graphical interfaces for filtering structured text. A prototype implementation is described.

A Reduced Distributed Splicing System for RE Languages

Abstract: In this paper we prove that each recursively enumerable language can be generated using a distributed splicing system with a fixed number of test tubes. This improves a recent result by Csuhaj-Varju, Kari, Paun, proving computational completeness only for a system with a number of tubes depending on the cardinality of the used alphabet.

Natural computation for natural language

Abstract: Computation not only takes place in provoked contexts of scientific experimentation, but in natural circumstances too. We are going to approach computation in natural contexts. How the nature computes? Turing machines and Chomsky grammars are rewriting systems, and the same is true for Post, Thue, Markov, Lindenmayer and other classes of axiomatic systems. If, among the whole set of natural objects, we focus natural language description, we must say that major trends in contemporary linguistics look at syntax as a rewriting process. Is rewriting unavoidable in this case, does our mind work by rewriting, does the nature compute in this way? We shall attempt to defend that the answer could be negative. The arguments will come from computability theory as well as from linguistics. First we'll formally explain the former ones, then informally the latter ones. With regard to computability theory arguments, we will see that, using the operation of adjoining, a large generative capacity is obtained. This is the case with contextual grammars. It has recently been proved that each recursively enumerable language is the quotient by a regular language of a language generated by a contextual grammar of a particular form. Thus, adjoining (paste) and quotient (cut) lead to computational universality. Recursively enumerable languages can also be characterized as the quotient by a regular language of a language generated by an insertion grammar. The same result is obtained if we take the splicing operation, a formal model of the DNA recombination. This is again a cut-and-paste operation. On the basis of the proof of this result, several further characterizations of recursively enumerable languages have been obtained. Computability theory, then, could be reconstructed without rewriting (and non-terminal symbols) and without any loss in power. Our first aim will be to show some formal aspects of such reconstruction. Later, we'll try to obtain some consequences for the future development of generative theory of natural language.

An hybrid language model for a continuous dictation prototype.

Abstract: This paper describes the combination of a stochastic language model and a formal grammar modeled such as a unification grammar. The stochastic model is trained over 42 million words extracted from Le Monde newspaper. The stochastic model is based on smoothed 3-gram and 3-class. The 3-class model is represented by a Markov chain made up of four states. Several experiments have been done to state which values are the best for specific training and test corpus. Experiments indicate that the unification grammar reduces strongly the number of hypothesis (sentences) produced by the stochastic model.

A Formal Syntax and a Formal Semantics for Open Estelle

Abstract: Estelle is an internationally standardized formal description technique (FDT) designed for the specification of distributed systems, in particular communication protocols. An Estelle specification describes a system of communicating components (module instances). The specified system is closed in a topological sense, i.e. it has no ability to interact with some environment. Because of this restriction, open systems can only be specified together with and incorporated with an environment. To overcome this restriction, we introduce a compatible extension of Estelle, called "Open Estelle". It allows the specification of (topologically) open systems, i.e. systems that have the ability to communicate with any environment through a well-defined external interface. We define aformal syntax and a formal semantics for Open Estelle, both based on and extending the syntax and semantics of Estelle. The extension is compatible syntactically and semantically, i.e. Estelle is a subset of Open Estelle. In particular, the formal semantics of Open Estelle reduces to the Estelle semantics in the special case of a closed system. Furthermore, we present a tool for the textual integration of open systems into environments specified in Open Estelle, and a compiler for the automatic generation of implementations directly from Open Estelle specifications.

Modelling spatial reasoning systems with shape algebras and formal logic

Abstract: The combination of the paradigms of shape algebras and predicate logic representations, used in a new method for describing designs, is presented. First-order predicate logic provides a natural, intuitive way of representing shapes and spatial relations in the development of complete computer systems for reasoning about designs. Shape algebraic formalisms have advantages over more traditional representations of geometric objects. Here we illustrate the definition of a large set of high-level design relations from a small set of simple structures and spatial relations, with examples from the domains of geographic information systems and architecture.

Teams in Grammar Systems: Sub-Context-Free Cases

Abstract: The study of teams in grammar systems so far has evolved around teams being formed from a finite number of sets of context-free productions. Here, the generative power of teams in grammar systems consisting of regular, linear and metalinear sets of productions is investigated.

Deterministic Cooperating Distributed Grammar Systems

Abstract: Subclasses of grammar systems that can facilitate parser construction appear to be of interest. In this paper, some syntactical conditions considered for strict deterministic grammars are extended to cooperating distributed grammar systems, restricted to the terminal derivation mode. Two variants are considered according to the level to which the conditions address. The local variant, which introduces strict deterministic restrictions for each component of the system apart, results in local unambiguity of the derivations. The total variant, which extends the strict deterministic constraints at the level of the entire system, results in some cases in global unambiguity of the derivations.

The Output-Store Formal Translator Directed by LR Parsing

Abstract: This paper presents a one-pass formal translator that can be constructed for each translation grammar with an LR(k) input grammar. The formal translator is the conventional LR parser whose operations are extended by actions performing both an output and a temporary storing of output symbols. The temporary storing of some symbols before their appending to the output string is implemented by using one synthesized attribute.

On Cooperating Distributed Uniformly Limited 0L Systems

Abstract: Cooperating distributed grammar systems [1] constitute a formal model of the blackboard model for problem solving. In this paper, we replace the grammars in such systems by uniformly k-limited 0L systems

Grammar Systems with Counting Derivation and Dynamical Priorities

Abstract: The paper deals with a new type of restriction considered for the cooperation protocol of grammar systems. The effect of this strategy is investigated for all modes of derivation. Some connections are made with the usual concept of fairness [1], [6] and that introduced for grammar systems [5].

Are There Formal Languages Complete for SymSPACE(log n)

Abstract: This article discusses the existence of SymSPACE(logn)-complete formal languages It is shown that a recent approach of Alvarez and Greenlaw to define symmetric versions of one-way devices doesn't lead to SymSPACE(log n) complete problems when applied to linear context-free or to one-counter languages

Characterization of RE Using CD Grammar Systems with Two Registers and RL Rules

Abstract: We prove that each recursively enumerable language can be generated by a cooperating distributed grammar system with two Q+ registers and right-linear rules.

Homomorphic Images os Sentential Forms and Terminating Grammars (Extended Abstract)

Abstract: We consider languages generated as homomorphic images of sentential form languages and related grammars. A characterization of these languages in terms of their topological properties is given. Previous hierarchy results are strengthened by constructing separating languages over a single letter alphabet. The relation to languages generated by terminating grammars is investigated.

A Note on the Incomparability of the EOL Family with Certain Families of Languages Generated by Cooperating Grammar Systems

Abstract: We show that the family of languages generated by cooperating distributed (CD) grammar systems with context-free components in the derivation modes=k,≥k, for k≥2, and the family of E0L languages are incomparable

EIKONES-an object-oriented language for image processing

Abstract: This paper presents an object oriented language, called EIKONES, for efficient and flexible image processing. The EIKONES language provides the user flexibility and friendliness for image processing which are not available in other image processing tools. The basic idea behind EIKONES is the consideration of the image processing algorithms as objects and the appropriate development of a formal grammar for its actual implementation. Results are provided by using the EIKONES language.

On Controlling Rewriting by Properties of Strings and Symbols

Abstract: In this paper we explore forms of organization of rewriting systems which allow the systematic modelling of systems for human-computer interaction and the control of their dynamics. To this end we exploit tools from formal languages, adopting forms of parallel rewriting from L-systems tradition. Based on this formalisation, a notion of controlled rewriting is proposed where information about how to rewrite strings is embedded into the strings themselves or in properties of symbols. The main contribution of the paper is the introduction of a variety of families of L-systems with new control mechanisms in their rewriting relations. Hierarchies in the families are discussed and some relations among them presented. We also start the exploration of the closure properties of these language families. Finally, we discuss some relations among the proposed families of L-systems and families of grammar systems.