Transcript Lecture 2 - ufal wiki

Leonid Iomdin
Institute for Information Transmission Problems,
Russian Academy of Sciences
[email protected], [email protected]
Program Overview: p. 1
 1. Basic Principles of The Meaning-Text theory by Igor
Mel’čuk. Language as a Universal Translator of Senses
to Texts and Texts to Senses. Text analysis and text
generation. The theory of integral linguistic
description by Juri Apresjan. The grammar and the
dictionary of language.
 2. Two syntactic levels of sentence representation:
surface syntax and deep syntax.
November 23, 2009. Lecture 2
2
Program Overview: p. 2
 3. The dependency tree structure as a syntactic
representation of the sentence. Dependency tree
vs. Constituent tree: advantages and drawbacks of
both types of representation. Limits of the
dependency tree. The hypothesis of two syntactic
starts.
 4. The notions of syntactic relation. Major classes of
syntactic relations: actant, attributive, coordinative
and auxiliary relation classes.
 5. The notion of syntactic feature. Syntactic features
vs. Semantic features.
November 23, 2009. Lecture 2
3
Program Overview: p. 3
 6. Actants and valencies. Active, passive and distant
valencies. The government pattern of a dictionary entry.
An overview of actant syntactic relations. The
predicative relation. The agentive relation. Completive
relations.
 7. An overview of attributive syntactic relations.
Grammatical Agreement. Numerals and Quantitative
Constructions. The system of Quantification Syntax of
Russian.
 8. Grammatical coordination as a type of grammatical
subordination. An overview of coordinative syntactic
relations.
November 23, 2009. Lecture 2
4
Program Overview: p. 4
 9. Auxiliary syntactic relations. Analytical grammatical
forms as an object of syntax.
 10 Microsyntax of Language. Minor Type Sentences.
Syntactic Idioms.
 11. Lexical Functions in the Dictionary and the
Grammar.
 12. Syntactic description and syntactic rules.
Dependency Syntax in NLP. Dependency Syntax in
Machine Translation. Syntactically Tagged Corpus of
Texts.
November 23, 2009. Lecture 2
5
Theoretical Background:
Meaning  Text Theory by
Igor Mel'čuk
November 23, 2009. Lecture 2
6
Assumption
Sense is a construct, an artificial
representation in a specially
designed semantic language
November 23, 2009. Lecture 2
7
Linguistic Disciplines
Syntax is the conversion of the
morphological representation
into a syntactic representation
and vice versa
November 23, 2009. Lecture 2
8
Surface Syntactic Representation (SSyntR)
of a Sentence
Mel'čuk, I. A , & Pertsov, N. V. (1987).
November 23, 2009. Lecture 2
9
Surface Syntactic Representation (SSyntR)
of a Sentence in ETAP-3
Mel'čuk, I. A , & Pertsov, N. V. (1987).
November 23, 2009. Lecture 2
10
Surface Syntax
 is the main linguistic discipline to which
this course is devoted: conversion between
deep morphological representation and
surface syntactic representation
November 23, 2009. Lecture 2
11
Morphological Analysis
• Input – a sentence in a conventional
orthographic form
• Output – a morphological structure of a
sentence
November 23, 2009. Lecture 2
12
Morphological Structure of a Sentence
• MorphS of a sentence is a sequence of
morphological structures of all words
belonging to the sentence
• MorphS of a word is the set of all MorphS
of all homonyms of this word
• MorphS of a homonym is the lexeme
name (lemma) plus part of speech plus a
set of all inflectional features
November 23, 2009. Lecture 2
13
Morphological Structure of a Sentence
• Morphological features are values of
morphological categories
November 23, 2009. Lecture 2
14
Morphological Categories
Different parts of speech have different
morphological categories
November 23, 2009. Lecture 2
15
Parts of Speech in English
Noun
Adjective
Article
Numeral
Verb
Adverb
Conjunction
Preposition
Particle
Interjection
November 23, 2009. Lecture 2
16
Morphological Features in English
Cases of Nouns
Main case
Possessive case
November 23, 2009. Lecture 2
17
Morphological Features in English
Cases of Personal Pronouns
Main case
Objective case
November 23, 2009. Lecture 2
18
Morphological Features in English
Number of Nouns and Verbs
Singular
Plural
November 23, 2009. Lecture 2
19
Morphological Features in English
Degrees of Comparison of Adjectives and Adverbs
Positive
Comparative
Superlative
November 23, 2009. Lecture 2
20
Morphological Features in English
Representation of Verbs
Main Form
Active participle
Passive participle
November 23, 2009. Lecture 2
21
Morphological Features in English
Tense of Verbs
Nonpast
Past
November 23, 2009. Lecture 2
22
Morphological Features in English
Person of Verbs
First
Second
Third
November 23, 2009. Lecture 2
23
Two types of Syntactic Representations
Constituent Tree Phrase Structure
S
NP
A
Small
VP
N
children
November 23, 2009. Lecture 2
V
N
like
ice-cream
24
Two types of Syntactic Representations
Constituent Tree Phrase Structure
November 23, 2009. Lecture 2
25
Two types of Syntactic Representations
Dependency Tree Structure
LIKE
predicative
modificative
CHILDREN
1st completive
ICE-CREAM
SMALL
November 23, 2009. Lecture 2
26
Two types of Syntactic Representations
Dependency Tree Structure
November 23, 2009. Lecture 2
27
Two types of Syntactic Representations
Constituent structure
OR
Dependency structure:
which is better?
November 23, 2009. Lecture 2
28
Two types of Syntactic Representations
Constituent structures focus on groups
of words,
while
Dependency structures focus on links
between individual words.
November 23, 2009. Lecture 2
29
Two types of Syntactic Representations
 Of course, both these properties of an utterance are
important.
In the dependency tree, we are unable to resolve certain
cases of conjunction reduction, cf.
young men and women
which will get a structure like
November 23, 2009. Lecture 2
30
Two types of Syntactic Representations
while this is easily resolved in phrase structure
representation:
(young men) and women ‘young men and any women’
vs.
young (men and women) ‘young men and young women’
November 23, 2009. Lecture 2
31
Two types of Syntactic Representations
 On the other hand, the dependency tree allows us to
distinguish between different types of noun phrases
like Project Challenge, which may either mean
 (1) ‘challenge of the project’ or
 (2) ‘project named challenge’.
November 23, 2009. Lecture 2
32
Two types of Syntactic Representations
1)
2)
November 23, 2009. Lecture 2
33
Two types of Syntactic Representations
 Besides, the dependency tree formalism is strong
enough to account for non-projective trees, which
is not so easily achievable in phrase structure
representations.
November 23, 2009. Lecture 2
34
Two types of Syntactic Representations
The project was so bad that the commission rejected it.
November 23, 2009. Lecture 2
35
Classes of Syntactic Relations
 1) actant relations;
 2) attributive relations;
 3) coordinative relations;
 4) auxiliary relations
November 23, 2009. Lecture 2
36
Actant Relations
 1) predicative relation;
 2) agentive relation;
 3) completive relations (1st completive to 5th
completive);
 4) copulative relation;
 5) prepositional relation
etc.
November 23, 2009. Lecture 2
37
Actants and Valencies
Several notions are needed:
 Predicate
 Situation
 Situation Participant, or Actant
 Valency (=valence)
 Frame representation
 Government Pattern
November 23, 2009. Lecture 2
38
Actants and Valencies
Two different sources of this approach:
 Linguistics (Lucien Tesnière, Charles
Fillmore, Jury Apresjan)
 Artificial Intelligence and Cognitive Science
(Marvin Minsky, Terry Winograd)
November 23, 2009. Lecture 2
39
Actants and Valencies
L. Tesnière. Éléments de syntaxe structurale,
Klincksieck, Paris 1959
Ch. Fillmore. Frame semantics and the nature of
language, 1976
Ju.Apresjan. Lexical Semantics. Moscow 1974
M.Minsky. A Framework for Representing
Knowledge, 1975
T. Winograd. Understanding Natural Language, 1972
November 23, 2009. Lecture 2
40
Actants and Valencies
SLEEP
SEE
GIVE
SELL
LEASE
CURE
rus. KOMANDIROVAT’ ‘send on an official trip’
November 23, 2009. Lecture 2
41
Actants and Valencies
There are three types of valencies:
 active
 passive
 distant
November 23, 2009. Lecture 2
42
Actants and Valencies
Active valencies
 transmission of [D2] personal data by
[D1] Europol to [D3] third States
 transmission by [D1] insects of [D2]
spores from [D3] diseased trees to [D4]
wounds on healthy trees
November 23, 2009. Lecture 2
43
Actants and Valencies
Passive valencies
 red ball
November 23, 2009. Lecture 2
44
Actants and Valencies
Distant valencies
 the ball is red
 I wanted John to do the job
 Nastassja Kinski was the favorite
actress of my sister.
 Nastassja Kinski was her favorite
actress.
November 23, 2009. Lecture 2
45
Actants’ Interplay
Population growth is the reason of
climate change
We cannot refund tickets for the reason
of adverse weather conditions
November 23, 2009. Lecture 2
46
Predicative Relation
The government member of the
predicative SSyntRel being invariably a
finite verb, its dependent member can
be one of the four items:
November 23, 2009. Lecture 2
47
Next lectures
 Actantial Syntactic Relations
(continuation). Attributive Relations
November 23, 2009. Lecture 2
48