Littérature scientifique sur le sujet « Grammatical formalisms »

The present paper is an introduction to unification as a formalism for writing grammars for natural languages. The paper is structured as follows. Section 1 briefly describes the history and the current scene of unification based grammar formalisms. Sections 2–3 describe the basic design of current formalisms. Section 4 constitutes a tutorial introduction to a representative unification based grammar formalism, the D–PATR system of Karttunen (1986). Sections 5—6 consider extensions of the unification formalism and its limitations. Section 7 examines implementation questions and addresses the question of the computational complexity of unification. — Some notes on terminology.

Grammatical Framework (GF) is a special-purpose functional language for defining grammars. It uses a Logical Framework (LF) for a description of abstract syntax, and adds to this a notation for defining concrete syntax. GF grammars themselves are purely declarative, but can be used both for linearizing syntax trees and parsing strings. GF can describe both formal and natural languages. The key notion of this description is a grammatical object, which is not just a string, but a record that contains all information on inflection and inherent grammatical features such as number and gender in natural languages, or precedence in formal languages. Grammatical objects have a type system, which helps to eliminate run-time errors in language processing. In the same way as a LF, GF uses dependent types in abstract syntax to express semantic conditions, such as well-typedness and proof obligations. Multilingual grammars, where one abstract syntax has many parallel concrete syntaxes, can be used for reliable and meaning-preserving translation. They can also be used in authoring systems, where syntax trees are constructed in an interactive editor similar to proof editors based on LF. While being edited, the trees can simultaneously be viewed in different languages. This paper starts with a gradual introduction to GF, going through a sequence of simpler formalisms till the full power is reached. The introduction is followed by a systematic presentation of the GF formalism and outlines of the main algorithms: partial evaluation and parser generation. The paper concludes by brief discussions of the Haskell implementation of GF, existing applications, and related work.

This paper presents some of the results of a larger study dedicated to the path of grammatical knowledge from the ancient Greek-Byzantine grammatical treatises to the Eastern Orthodox Slavic world, to the Bulgarian grammatical tradition from the Na-tional Revival period. The focus is on the syntactic element of the grammatical description. A formal notation of the sentence sections in the grammars of Avram Mrazović, Yuriy Venelin and Ivan Bogorov is enclosed to the end of comparing the “art and craft of writing grammars”. Grammatical formalisms have proved to be a reliable tool in the analytical procedures in the phylogenetic study of the Bulgarian syntactic tradition, as well as in the configurational analysis of the sentence, which departs from the practice of asking “questions” and looks into the fundamental property of “syntactic function” through the prism of modern grammar. Keywords: Bulgarian syntactic tradition, grammaticography, grammatical forma-lisms

Applying grammatical formalisms to engineering problems requires consideration of spatial, functional, and behavioral design attributes. This paper explores structural design languages and semantics for the generation of feasible and purposeful discrete structures. In an application of shape annealing, a combination of grammatical design generation and search, to the generation of discrete structures, rule syntax, and semantics are used to model desired relations between structural form and function as well as control design generation. Explicit domain knowledge is placed within the grammar through rule and syntax formulation, resulting in the generation of only forms that make functional sense and adhere to preferred visual styles. Design interpretation, or semantics, is then used to select forms that meet functional and visual goals. The distinction between syntax used in grammar rules to explicitly drive geometric design and semantics used in design interpretation to implicitly guide geometric form is shown. Overall, the designs presented show the validity of applying a grammatical formalism to an engineering design problem and illustrate a range of possibilities for modeling functional and visual design criteria.

Summary We examine various issues faced during the elaboration of lexical disambiguators, e.g. issues related with linguistic analyses underlying disambiguators, and we exemplify these issues with grammatical constraints. We also examine computational problems and show how they are connected with linguistic problems: the influence of the granularity of tagsets, the definition of realistic and useful objectives, and the construction of the data required for the reduction of ambiguity. We show why a formalism is required for automatic ambiguity reduction, we analyse its function and we present a typology of such formalisms.

Abstract Aravind Joshi famously hypothesized that natural language syntax was characterized (in part) by mildly context-sensitive generative power. Subsequent work in mathematical linguistics over the past three decades has revealed surprising convergences among a wide variety of grammatical formalisms, all of which can be said to be mildly context-sensitive. But this convergence is not absolute. Not all mildly context-sensitive formalisms can generate exactly the same stringsets (i.e. they are not all weakly equivalent), and even when two formalisms can both generate a certain stringset, there might be differences in the structural descriptions they use to do so. It has generally been difficult to find cases where such differences in structural descriptions can be pinpointed in a way that allows linguistic considerations to be brought to bear on choices between formalisms, but in this paper we present one such case. The empirical pattern of interest involves wh-movement dependencies in languages that do not enforce the wh-island constraint. This pattern draws attention to two related dimensions of variation among formalisms: whether structures grow monotonically from one end to another, and whether structure-building operations are conditioned by only a finite amount of derivational state. From this perspective, we show that one class of formalisms generates the crucial empirical pattern using structures that align with mainstream syntactic analysis, and another class can only generate that same string pattern in a linguistically unnatural way. This is particularly interesting given that (i) the structurally-inadequate formalisms are strictly more powerful than the structurally-adequate ones from the perspective of weak generative capacity, and (ii) the formalism based on derivational operations that appear on the surface to align most closely with the mechanisms adopted in contemporary work in syntactic theory (merge and move) are the formalisms that fail to align with the analyses proposed in that work when the phenomenon is considered in full generality.

This paper has two purposes. First, it suggests a formal approach for specifying and verifying lingware. This approach is based on a unified notation of the main existing formalisms for describing linguistic knowledge (i.e. Formal Grammars, Unification Grammars, HPSG, etc.) on the one hand, and the integration of data and processing on the other. Accordingly, a lingware specification includes all related aspects in a unified framework. This facilitates the development of a lingware system, since one has to follow a single development process instead of two separate ones. Secondly, it presents an environment for the formal specification of lingware, based on the suggested approach, which is neither restricted to a particular kind of application nor to a particular class of linguistic formalisms. This environment provides interfaces enabling the specification of both linguistic knowledge and functional aspects of a lingware system. Linguistic knowledge is specified with the usual grammatical formalisms, whereas functional aspects are specified with a suitable formal notation. Both descriptions will be integrated into the same framework to obtain a complete requirement specification that can be refined towards an executable program.

AbstractDue to recent developments in the area of computational formalisms for linguistic representation, the task of designing a parser for a specified natural language is now shifted to the problem of designing its grammar in certain formal ways. This paper describes the results of a project whose aim was to design a formal grammar for modern Hebrew. Such a formal grammar has never been developed before. Since most of the work on grammatical formalisms was done without regarding Hebrew (and other Semitic languages as well), we had to choose a formalism that would best fit the specific needs of the language. This part of the project has been described elsewhere. In this paper we describe the details of the grammar we developed. The grammar deals with simple, subordinate and coordinate sentences as well as interrogative sentences. Some structures were thoroughly dealt with, among which are noun phrases, verb phrases, adjectival phrases, relative clauses, object and adjunct clauses; many types of adjuncts; subcategorization of verbs; coordination; numerals, etc. For each phrase the parser produces a description of the structure tree of the phrase as well as a representation of the syntactic relations in it. Many examples of Hebrew phrases are demonstrated, together with the structure the parser assigns them. In cases where more than one parse is produced, the reasons of the ambiguity are discussed.

The formalism for Lexical-Functional Grammar (LFG) was introduced in the 1980s as one of the first constraint-based grammatical formalisms for natural language. It has led to substantial contributions to the linguistic literature and to the construction of large-scale descriptions of particular languages. Investigations of its mathematical properties have shown that, without further restrictions, the recognition, emptiness, and generation problems are undecidable, and that they are intractable in the worst case even with commonly applied restrictions. However, grammars of real languages appear not to invoke the full expressive power of the formalism, as indicated by the fact that algorithms and implementations for recognition and generation have been developed that run—even for broad-coverage grammars—in typically polynomial time. This article formalizes some restrictions on the notation and its interpretation that are compatible with conventions and principles that have been implicit or informally stated in linguistic theory. We show that LFG grammars that respect these restrictions, while still suitable for the description of natural languages, are equivalent to linear context-free rewriting systems and allow for tractable computation.