Showing papers on "Context-sensitive grammar published in 1986"
TL;DR: A formal model of the mental representation of task languages is presented, a metalanguage for defining task-action grammars (TAG) that rewrite simple tasks into action specifications that make predictions about the relative learnability of different task language designs.
Abstract: A formal model of the mental representation of task languages is presented. The model is a metalanguage for defining task-action grammars (TAG): generative grammars that rewrite simple tasks into action specifications. Important features of the model are (a) Identification of the "simple-tasks" that users can perform routinely and that require no control structure; (b) Representation of simple-tasks by collections of semantic components reflecting a categorization of the task world; (c) Marking of tokens in rewrite rules with the semantic features of the task world to supply selection restrictions on the rewriting of simple-tasks into action specifications. This device allows the representation of family resemblances between individual task-action mappings. Simple complexity metrics over task-action grammars make predictions about the relative learnability of different task language designs. Some empirical support for these predictions is derived from the existing empirical literature on command language learning, and from two unreported experiments. Task-action grammars also provide designers with an analytic tool for exposing the configural properties of task languages.
328 citations
25 Aug 1986
TL;DR: The strategies and potentials of CUGs justify their further exploration in the wider context of research on unification grammars, and approaches to selected linguistic phenomena such as long-distance dependencies, adjuncts, word order, and extraposition are discussed.
Abstract: Categorial unification grammars (CUGs) embody the essential properties of both unification and categorial grammar formalisms. Their efficient and uniform way of encoding linguistic knowledge in well-understood and widely used representations makes them attractive for computational applications and for linguistic research.In this paper, the basic concepts of CUGs and simple examples of their application will be presented. It will be argued that the strategies and potentials of CUGs justify their further exploration in the wider context of research on unification grammars. Approaches to selected linguistic phenomena such as long-distance dependencies, adjuncts, word order, and extraposition are discussed.
160 citations
TL;DR: The membership problem for fixed context-sensitive languages is polynomial if the right hand side of every production is strictly longer than the left hand side.
104 citations
25 Aug 1986
TL;DR: It is shown that Head Languages are included in Tree Adjoining Languages and that Tree Adjoined Grammars are equivalent to a modification of Head Grammar called Modified Head GramMars.
Abstract: In this paper we discuss the formal relationship between thw classes of languages generated by Tree Adjoining Grammars and Head Grammars. In particular, we show that Head Languages are included in Tree Adjoining Languages and that Tree Adjoining Grammars are equivalent to a modification of Head Grammars called Modified Head Grammars. The inclusion of MHL in HL, and thus the equivalence of HG's and TAG's in the most general case remains to be established.
38 citations
02 Dec 1986
TL;DR: It turns out that each equivalence class in the theory of graph grammars is uniquely represented by a canonical derivation, which is minimal with respect to a delay index.
Abstract: The aim of this paper is to outline the support the theory of graph grammars offers to deal with parallelism and concurrency. The considerations in Part 1 are based on derivations in graph grammars (using a simple, but general framework). Sequentialization and parallelization of derivation steps are studied. From the point of view of concurrency, these constructions induce an equivalence on derivations. It turns out that each equivalence class is uniquely represented by a canonical derivation, which is minimal with respect to a delay index. Part 2 deals with a kind of non-sequential processes in graph grammars (overcoming the sequentiality of derivations).
37 citations
32 citations
TL;DR: The complexity of (the membership problem for) the class of regular DNLC grammars is investigated and it is found that it provides a useful framework for the theory of concurrent systems based on the Theory of traces.
28 citations
TL;DR: It is shown that the output language (i.e., the range of the translation) of a SAG is log-space reducible to a context-free language.
Abstract: A string-valued attribute grammar (SAG) has a semantic domain of strings over some alphabet, with concatenation as basic operation. It is shown that the output language (i.e., the range of the translation) of a SAG is log-space reducible to a context-free language.
26 citations
IBM1
TL;DR: An effective method for the execution of recursive attribute grammars has been defined and applied and generated Prolog code stands in direct relation to its attribute grammar.
Abstract: This paper describes an algorithm for compiling attribute grammars into Prolog. The attribute grammars may include inherited and synthesized attributes and contain recursive (circular) definitions. The semantics of the recursive definitions is defined in terms of a fixed-point finding function. The generated Prolog code stands in direct relation to its attribute grammar, where logical variables play the role of synthesized or inherited attributes. Thus an effective method for the execution of recursive attribute grammars has been defined and applied.
25 citations
10 Jul 1986
TL;DR: The absence of mirror-image constructions in human languages means that it is not enough to extend Context-free Grammars in the direction of context-sensitivity, and a class of grammars must be found which handles (context-sensitive) copying but not ( context-free) mirror images, suggesting that human linguistic processes use queues rather than stacks.
Abstract: The documentation of (unbounded-length) copying and cross-serial constructions in a few languages in the recent literature is usually taken to mean that natural languages are slightly context-sensitive. However, this ignores those copying constructions which, while productive, cannot be easily shown to apply to infinite sublanguages. To allow such finite copying constructions to be taken into account in formal modeling, it is necessary to recognize that natural languages cannot be realistically represented by formal languages of the usual sort. Rather, they must be modeled as families of formal languages or as formal languages with indefinite vocabularies. Once this is done, we see copying as a truly pervasive and fundamental process in human language. Furthermore, the absence of mirror-image constructions in human languages means that it is not enough to extend Context-free Grammars in the direction of context-sensitivity. Instead, a class of grammars must be found which handles (context-sensitive) copying but not (context-free) mirror images. This suggests that human linguistic processes use queues rather than stacks, making imperative the development of a hierarchy of Queue Grammars as a counterweight to the Chomsky Grammars. A simple class of Context-free Queue Grammars is introduced and discussed.
TL;DR: This work adapts the theory of probabilistic grammars to the prediction of switchpoint abundance for a given bilingual situation and applies this to a number of language pairs exhibiting diverse word-order contrasts.
Abstract: How can we combine the grammars of two languages to model bilingual behaviour such as code-switching under the equivalence constraint on word order? We answer this question on the formal level, making use of context-free grammars for both unilingual and bilingual behaviour. Our solution satisfies a number of conditions on the language assigned (if any) to higher-order constituents in the phrase structure. Bilingual sentences are seen to be often ambiguous with respect to this assignment. We adapt the theory of probabilistic grammars to the prediction of switchpoint abundance for a given bilingual situation and we apply this to a number of language pairs exhibiting diverse word-order contrasts. We show how to count the number of bilingual sentences which are code-switched equivalents of a given sentence.
10 Jul 1986
TL;DR: The relationship between the two grammatical formalisms: Tree Adjoining Grammars and Head Grammar is examined and a discussion comparing the linguistic expressiveness of the two formalisms is discussed.
Abstract: We examine the relationship between the two grammatical formalisms: Tree Adjoining Grammars and Head Grammars. We briefly investigate the weak equivalence of the two formalisms. We then turn to a discussion comparing the linguistic expressiveness of the two formalisms.
02 Dec 1986
TL;DR: Non-sequential processes in graph grammars are introduced extending the repertoire of parallelism and concurrency known for graph grammar derivations, and conflict solutions are investigated by applying techniques and results from graph grammar theory.
Abstract: Non-sequential processes in graph grammars are introduced extending the repertoire of parallelism and concurrency known for graph grammar derivations. They are intended to describe the behaviour of systems explicitly where states or data may be distributed and actions may take place concurrently. Our notion of a process is liberal enough to include conflicts among actions so that it reflects potential activities rather than actual running of the system in general. The problem of detecting conflicts in a process is solved by a procedure transforming arbitrary conflicts into local and hence observable ones. For special situations conflict solutions are investigated by applying techniques and results from graph grammar theory.
Proceedings Article•
02 Dec 1986
TL;DR: This paper presents a formalism for actor systems in the framework of graph grammars, a model of massively parallel systems based on asynchronous message passing, that is motivated, motivated, and illustrated by examples.
Proceedings Article•
11 Aug 1986
TL;DR: The reasoning behind the selection and design of a parser for the Lingo project on natural language interfaces at MCC is presented, and a variant of chart parsing that uses a best-first control structure managed on an agenda as a control structure is chosen.
Abstract: This paper presents the reasoning behind the selection and design of a parser for the Lingo project on natural language interfaces at MCC. The major factors in the selection of the parsing algorithm were the choices of having a syntactically based grammar, using a graph-unification-based representation language, using Combinatory Categorial Grammars, and adopting a one-to-many mapping from syntactic bracketings to semantic representations in certain cases. The algorithm chosen is a variant of chart parsing that uses a best-first control structure managed on an agenda. It offers flexibility for these natural language processing applications by allowing for best-first tuning of parsing for particular grammars in particular domains while at the same time allowing exhaustive enumeration of the search space during grammar development. Efficiency advantages of this choice for graph-unification-based representation languages are outlined, as well as a number of other advantages that acrue to this approach by virtue of its use of an agenda as a control structure. We also mention two useful refinements to the basic best-first chart parsing algorithm that have been implemented in the Lingo project.
TL;DR: A shape grammar formalism which accounts for most aspects of 2-D shape, a parsing mechanism which uses constraints between pieces of the shape, and an automatic method to compute constraint relations between the vocabulary symbols of theshape grammar are proposed.
01 Aug 1986-Graphical Models \/graphical Models and Image Processing \/computer Vision, Graphics, and Image Processing
TL;DR: This paper investigates the basic properties of the class of neighborhood-uniform nodel label controlled (NUNLC) graph grammars and demonstrates that a number of basic properties are decidable for theclass of NUNLC grammar—many of them are undecidable in the whole class of NLC Grammars.
Abstract: This paper investigates the basic properties of the class of neighborhood-uniform nodel label controlled (NUNLC) graph grammars The class of NUNLC grammars is distinguished by requiring a very natural restriction on the connection relations of NLC grammars The restriction implies “Church-Rosser property” of derivations in an NUNLC grammar, which makes the class of NUNLC grammars “technically easier” to investigate A number of combinatorial properties of the languages generated by the class of NUNLC grammars are proved Also, it is demonstrated that a number of basic properties are decidable for the class of NUNLC grammars—many of them are undecidable in the whole class of NLC grammars
25 Aug 1986
TL;DR: The weak generative capacity of a class of parenthesis free categorial grammars derived from those of Ades and Steedman are studied by varying the set of reduction rules and a context sensitive language is obtained.
Abstract: We study the weak generative capacity of a class of parenthesis free categorial grammars derived from those of Ades and Steedman by varying the set of reduction rules. With forward cancellation as the only rule, the grammars are weakly equivalent to context free grammars. When a backward combination rule is added, it is no longer possible to obtain all the context-free language. With suitable restriction of the forward partial rule, the languages are still context-free and a push-down automaton can be used for recognition. Using the unrestricted rule of forward partial combination, a context sensitive language is obtained.
TL;DR: An algorithm is presented which given an arbitrary A-free context-free grammar produces an equivalent context- free grammar in 2 Greibach normal form, and the upper bound on the size of the resulting grammar is not bigger than the bounds known for other algorithms for converting context- Free grammars into equivalent Context-free Grammars in GreibACH normal form.
Abstract: We present an algorithm which given an arbitrary A-free context-free grammar produces an equivalent context-free grammar in 2 Greibach normal form. The upper bound on the size of the resulting grammar in terms of the size of the initially given grammar is given. Our algorithm consists of an elementary construction, while the upper bound on the size of the resulting grammar is not bigger than the bounds known for other algorithms for converting context-free grammars into equivalent context-free grammars in Greibach normal form.
TL;DR: To show the practical feasibility of attribute grammar inversion, experience in inverting an attribute grammar used as an interface for a formal database accessing language, SQL, is related; the attributed grammar is used to paraphrase SQL database queries in English.
Abstract: Attribute grammars constitute a formal mechanism for specifying translations between languages; from a formal description of the translation, a translator can be automatically constructed. This process is taken one step further; given an attribute grammar specifying the translation from language L1 to language L2, the question of whether the inverse attribute grammar specifying the inverse translation from L2 to L1 can be automatically generated is addressed. It is shown how to solve this problem for a restricted subset of attribute grammars. This inversion process allows compatible two-way translators to be generated from a single description. To show the practical feasibility of attribute grammar inversion, experience in inverting an attribute grammar used as an interface for a formal database accessing language, SQL, is related. The attributed grammar is used to paraphrase SQL database queries in English.
TL;DR: It is shown that the direction-independent restriction does not affect the generative powers of MAG, but it does, however, affect theGenerative power of a restricted version of ∗AG, i.e., connected ∗-array grammars.
TL;DR: This work has shown that Parser tables of predictive LL-parsers for extended grammars can be generated very efficiently if the length of look-ahead is 1 and the generation time is proportional to the size of the parser table.
Abstract: Extended context-free grammars also called regular right part grammars allow for compact and readable descriptions of the syntax of programming languages. Recursion in conventional context-free grammars can in most cases be replaced by iteration. Parser tables of predictive LL-parsers for extended grammars can be generated very efficiently if the length of look-ahead is 1. The generation time is proportional to the size of the parser table, that is the product of grammar size and number of terminal symbols.
02 Dec 1986
TL;DR: The notion of graphic grammars is presented, various programming implementations will be discussed and many motivating examples will be given.
Abstract: Graphics are graphs with attributes at their vertices. Graphic grammars are natural extensions of graph and attribute grammars with rules that are attributed extensions of the “pushout” productions of graph grammars. The notion of graphic grammars is presented and various programming implementations will be discussed. Many motivating examples will be given, including
Journal Article•
TL;DR: Functional abstraction over grammar rules enables the specification and processing of context sensitive language syntax aspects in a functional style.
Journal Article•
Proceedings Article•
11 Aug 1986
TL;DR: A restrictive grammar formalism for logic programming languages is presented that imposes some of the constraints suggested by recent Chomskian linguistic theory, which allows for relatively elegant characterizations of natural languages that can be translated into efficient prolog parsers.
Abstract: A parser formalism for natural languages that is so restricted as to rule out the definition of linguistic structures that do not occur in any natural language can make the task of grammar construction easier, whether it is done manually (by a programmer) or automatically (by a grammar induction system). A restrictive grammar formalism for logic programming languages is presented that imposes some of the constraints suggested by recent Chomskian linguistic theory. In spite of these restrictions, this formalism allows for relatively elegant characterizations of natural languages that can be translated into efficient prolog parsers.
TL;DR: A direction independent variant of the standard normal form for context-sensitive grammars is given: the context-free productions are of the form A → a or A → BC and thecontext-sensitive productions areOf the form AB → AC or BA → CA, where AB →AC is a production if and only if BA →CA is aProduction.
Abstract: A direction independent variant of the standard normal form for context-sensitive grammars is given: the context-free productions are of the form A → a or A → BC and the context-sensitive productions are of the form AB → AC or BA → CA , where AB → AC is a production if and only if BA → CA is a production. The equivalence of these grammars with the context-sensitive grammars is proved.