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Phrase Structure Rules
Phrase structure rules are a type of rewrite rule used to describe a given language's syntax and are closely associated with the early stages of transformational grammar, proposed by Noam Chomsky in 1957. They are used to break down a natural language sentence into its constituent parts, also known as syntactic categories, including both lexical categories (parts of speech) and phrasal categories. A grammar that uses phrase structure rules is a type of phrase structure grammar. Phrase structure rules as they are commonly employed operate according to the constituency relation, and a grammar that employs phrase structure rules is therefore a ''constituency grammar''; as such, it stands in contrast to ''dependency grammars'', which are based on the dependency relation. Definition and examples Phrase structure rules are usually of the following form: :A \to B \quad C meaning that the constituent A is separated into the two subconstituents B and C. Some examples for English are a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rewrite Rule
In mathematics, computer science, and logic, rewriting covers a wide range of methods of replacing subterms of a formula with other terms. Such methods may be achieved by rewriting systems (also known as rewrite systems, rewrite engines, or reduction systems). In their most basic form, they consist of a set of objects, plus relations on how to transform those objects. Rewriting can be non-deterministic. One rule to rewrite a term could be applied in many different ways to that term, or more than one rule could be applicable. Rewriting systems then do not provide an algorithm for changing one term to another, but a set of possible rule applications. When combined with an appropriate algorithm, however, rewrite systems can be viewed as computer programs, and several theorem provers and declarative programming languages are based on term rewriting. Example cases Logic In logic, the procedure for obtaining the conjunctive normal form (CNF) of a formula can be implemented as a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Verb Phrase
In linguistics, a verb phrase (VP) is a syntactic unit composed of a verb and its arguments except the subject of an independent clause or coordinate clause. Thus, in the sentence ''A fat man quickly put the money into the box'', the words ''quickly put the money into the box'' constitute a verb phrase; it consists of the verb ''put'' and its arguments, but not the subject ''a fat man''. A verb phrase is similar to what is considered a ''predicate'' in traditional grammars. Verb phrases generally are divided among two types: finite, of which the head of the phrase is a finite verb; and nonfinite, where the head is a nonfinite verb, such as an infinitive, participle or gerund. Phrase structure grammars acknowledge both types, but dependency grammars treat the subject as just another verbal dependent, and they do not recognize the finite verbal phrase constituent. Understanding verb phrase analysis depends on knowing which theory applies in context. In phrase structure grammars In ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Minimalist Program
In linguistics, the minimalist program is a major line of inquiry that has been developing inside generative grammar since the early 1990s, starting with a 1993 paper by Noam Chomsky. Following Imre Lakatos's distinction, Chomsky presents minimalism as a program, understood as a mode of inquiry that provides a conceptual framework which guides the development of linguistic theory. As such, it is characterized by a broad and diverse range of research directions. For Chomsky, there are two basic minimalist questions — What is language? and Why does it have the properties it has? — but the answers to these two questions can be framed in any theory.Boeckx, Cedric ''Linguistic Minimalism. Origins, Concepts, Methods and Aims'', pp. 84 and 115. Conceptual framework Goals and assumptions Minimalism is an approach developed with the goal of understanding the nature of language. It models a speaker's knowledge of language as a computational system with one basic operation, namel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Passivization
A passive voice construction is a grammatical voice construction that is found in many languages. In a clause with passive voice, the grammatical subject expresses the ''theme'' or ''patient'' of the main verb – that is, the person or thing that undergoes the action or has its state changed. This contrasts with active voice, in which the subject has the agent role. For example, in the passive sentence "The tree was pulled down", the subject (''the tree'') denotes the patient rather than the agent of the action. In contrast, the sentences "Someone pulled down the tree" and "The tree is down" are active sentences. Typically, in passive clauses, what is usually expressed by the object (or sometimes another argument) of the verb is now expressed by the subject, while what is usually expressed by the subject is either omitted or is indicated by some adjunct of the clause. Thus, turning an active sense of a verb into a passive sense is a valence-decreasing process ("detransitivizi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Negation (linguistics)
In linguistics and grammar, affirmation (abbreviated ) and negation () are ways in which grammar encodes positive and negative polarity into verb phrases, clauses, or other utterances. An affirmative (positive) form is used to express the validity or truth of a basic assertion, while a negative form expresses its falsity. For example, the affirmative sentence "Jane is here" asserts that it is true that Jane is currently located near the speaker. Conversely, the negative sentence "Jane is not here" asserts that it is not true that Jane is currently located near the speaker. The grammatical category associated with affirmatives and negatives is called polarity. This means that a clause, sentence, verb phrase, etc. may be said to have either affirmative or negative polarity (its polarity may be either affirmative or negative). Affirmative is typically the unmarked polarity, whereas a negative statement is marked in some way. Negative polarity can be indicated by negating words or pa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Immediate Constituent Analysis
In linguistics, immediate constituent analysis or IC analysis is a method of sentence analysis that was first mentioned by Leonard Bloomfield and developed further by Rulon Wells. The process reached a full-blown strategy for analyzing sentence structure in the early works of Noam Chomsky. The practice is now widespread. Most tree structures employed to represent the syntactic structure of sentences are products of some form of IC-analysis. The process and result of IC-analysis can, however, vary greatly based upon whether one chooses the constituency relation of phrase structure grammars (= constituency grammars) or the dependency relation of dependency grammars as the underlying principle that organizes constituents into hierarchical structures. IC-analysis in phrase structure grammars Given a phrase structure grammar (= constituency grammar), IC-analysis divides up a sentence into major parts or immediate constituents, and these constituents are in turn divided into further imme ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dendrogram
A dendrogram is a diagram representing a tree. This diagrammatic representation is frequently used in different contexts: * in hierarchical clustering, it illustrates the arrangement of the clusters produced by the corresponding analyses. * in computational biology, it shows the clustering of genes or samples, sometimes in the margins of heatmaps. * in phylogenetics, it displays the evolutionary relationships among various biological taxa. In this case, the dendrogram is also called a phylogenetic tree. The name ''dendrogram'' derives from the two ancient greek words (), meaning "tree", and (), meaning "drawing, mathematical figure". Clustering example For a clustering example, suppose that five taxa (a to e) have been clustered by UPGMA based on a matrix of genetic distances. The hierarchical clustering dendrogram would show a column of five nodes representing the initial data (here individual taxa), and the remaining nodes represent the clusters to which the dat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parse Tree
A parse tree or parsing tree or derivation tree or concrete syntax tree is an ordered, rooted tree that represents the syntactic structure of a string according to some context-free grammar. The term ''parse tree'' itself is used primarily in computational linguistics; in theoretical syntax, the term ''syntax tree'' is more common. Concrete syntax trees reflect the syntax of the input language, making them distinct from the abstract syntax trees used in computer programming. Unlike Reed-Kellogg sentence diagrams used for teaching grammar, parse trees do not use distinct symbol shapes for different types of constituents. Parse trees are usually constructed based on either the constituency relation of constituency grammars (phrase structure grammars) or the dependency relation of dependency grammars. Parse trees may be generated for sentences in natural languages (see natural language processing), as well as during processing of computer languages, such as programming languages. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Colorless Green Ideas Sleep Furiously
''Colorless green ideas sleep furiously'' is a sentence composed by Noam Chomsky in his 1957 book ''Syntactic Structures'' as an example of a sentence that is grammatically well-formed, but semantically nonsensical. The sentence was originally used in his 1955 thesis ''The Logical Structure of Linguistic Theory'' and in his 1956 paper "Three Models for the Description of Language". There is no obvious understandable meaning that can be derived from it, which demonstrates the distinction between syntax and semantics, and the idea that a syntactically well-formed sentence is not guaranteed to be semantically well-formed as well. As an example of a category mistake, it was used to show the inadequacy of certain probabilistic models of grammar, and the need for more structured models. Senseless but grammatical Chomsky writes in his 1957 book ''Syntactic Structures'': It is fair to assume that neither sentence (1) nor (2) (nor indeed any part of these sentences) has ever occurred i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Semantics
Semantics (from grc, σημαντικός ''sēmantikós'', "significant") is the study of reference, meaning, or truth. The term can be used to refer to subfields of several distinct disciplines, including philosophy Philosophy (from , ) is the systematized study of general and fundamental questions, such as those about existence, reason, knowledge, values, mind, and language. Such questions are often posed as problems to be studied or resolved. Some ..., linguistics and computer science. History In English, the study of meaning in language has been known by many names that involve the Ancient Greek word (''sema'', "sign, mark, token"). In 1690, a Greek rendering of the term ''semiotics'', the interpretation of signs and symbols, finds an early allusion in John Locke's ''An Essay Concerning Human Understanding'': The third Branch may be called [''simeiotikí'', "semiotics"], or the Doctrine of Signs, the most usual whereof being words, it is aptly enough ter ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Grammaticality
In linguistics, grammaticality is determined by the conformity to language usage as derived by the grammar of a particular speech variety. The notion of grammaticality rose alongside the theory of generative grammar, the goal of which is to formulate rules that define well-formed, grammatical, sentences. These rules of grammaticality also provide explanations of ill-formed, ungrammatical sentences. In theoretical linguistics, a speaker's judgement on the well-formedness of a linguistic 'string'—called a grammaticality judgement—is based on whether the sentence is interpreted in accordance with the rules and constraints of the relevant grammar. If the rules and constraints of the particular lect are followed, then the sentence is judged to be grammatical. In contrast, an ungrammatical sentence is one that violates the rules of the given language variety. Linguists use grammaticality judgements to investigate the syntactic structure of sentences. Generative linguists are la ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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