CS544: Lecture 3: Syntax and Compositional Semantics of the Noun Phrase

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CS544 Lecture 3Syntax and Compositional
Semantics of the Noun Phrase
March 1, 2011

• Jerry R. Hobbs
• USC/ISI
• Marina del Rey, CA

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Noun Phrases
S
Last time we elaborated on VPs.
NP
VP
NP
V
This time well elaborate on NPs.
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The Relevant Parts of Speech
Noun (NN, NNS) singular and plural The _____
is ... Verb (VBN, VBG) broken,
breaking _____-ing Adjective (JJ, JJR, JJS)
good, better, best The ____ thing is
... Adverb (RB) very often ____-ly
Pronoun (PP) I, you, he, she, it, we, they,
anyone, ... Determiner and quantifies (DT) a,
the, some, .... Preposition (IN) of, in, to,
during, before, ...
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The Structure of the NP
the three tall government buildings in Chicago
that I saw
right modifiers, noun complements
left modifiers
head noun
noun group
the three tall gray U.S. government buildings
determiners, numbers, quantifiers
prenominal nouns
adjectives
head noun
In this order.
NP --gt DT JJ NN NN NNS .... You can use
this structure to tell what part of speech a word
is
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Nominal Compounds
One or more nouns can be placed before the head
noun This says only that some relation occurs
between the adjacent nouns or noun
sequences turpentine jar pension fund
air strike city lights language origin
grammar induction human languages
gt turpentine(x) nn(x,y) jar(y)
Bracketing ambiguities Stanford
Research Institute vs. cancer research
institute
gt cancer(x) research(y) nn(x,y)
institute(z) nn(y,z)
What about State pension funds Grammar
induction techniques Wall Street reform
effort California Public Employees
Retirement System
TreeBank does not tag these -- too hard to
explain to annotators
Noun-like adjectives can appear in this position
too.
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The Adjective Position
A sequence of adjectives in their absolute,
comparative, or superlative forms big
investors the new chief executive
a ferocious fire fight the nations biggest
public pension fund the Talibans ideological
agenda a cursory look different sentences
unannotated textual input
Present and Past Participles can occur in the
adjective position supporting air strikes
resulting brawl numbed reflection
stepped-up reform effort Present
Participles can occur in prenominal noun
position parking spaces its cratering
record
Note incorporated particle
Adverbs can modify the adjectives or
participles past internally driven geologic
activity
NN
Systematic ambiguity between adjective and
prenominal noun criminal lawyer
resulting brawl vs. parking spaces
JJ
gt criminal(x) lawyer(x) vs. criminal(x)
nn(x,y) lawyer(y)
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Other Adjective Position Constructions
Measure phrases 10-year fund veteran, 12.2
rise, six-foot high fence
Note use of singular
Hyphenated passives with nouns Los
Angeles-based company cement-lined
ramp Hyphenated present participle
(pre-participle noun is object)
money-losing investments Hyphenated or
unhyphenated adjective-noun
medium-resolution images higher level units
finite state languages
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Determiners
The order of determiners (quantifiers, numbers)
is a very random phenomenon that defies
general principles not as few as ten too many
other books All the forest was destroyed
any such book All a forest was
destroyed such any book

a such book the three other books
such a book three other books
the other three books
all three books other the three books
both two books other three books
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Some Determiner Phrases
Definite, Indefinite, Demonstrative the, a,
that, those Possessive Pronouns its, his,
our, their, your Quantifiers each, all, such,
An Ambiguity some situations vs some
computer program little (evidence) Determiner
or Adjective? other, our own Numbers and
Related Words two, 67 billion, several, many,
most,
four and a half (glasses) Complex
Determiners all our, all that, only a few,
the two, just one or two, more than 100,
a net 1,000, every last (one), the past 25
(millennia)
Possessive NPs also function as determiners the
nations biggest public pension fund
Afghanistans Uruzgan Valley Saturns
satellites
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Count Nouns vs. Mass Nouns
Count nouns in the singular require a
determiner I showed him an example.
I showed him example. Mass nouns dont
require a determiner in the singular I
gave him wine. When mass nouns do have a
determiner, it often means a kind rather
than an instance. I gave him a good
wine. ( a good kind of wine) But there are
many many idiomatic exceptions For
example, by surprise, in front, in mind,
He is president
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Structure of NPs Left Modifiers
all the many tall educated Washington
presidential foreign policy advisors

Head noun advisor(e0,x)


Plural(e1,x,s)
Prenominal nouns Washington(e2,w)
nn(e3,w,x)
Also noun-like Adjs president(e3,y)
nn(e4,y,x)
Adjectives tall(e5,x)
Also vbn, vbg educate(e6,z,x)
Quantifiers, Numbers many(e7,s) (property
of the set in plurals) Determiner
the(e8,x, ....e1) (relation
between entity x and description given by rest of
NP) Possessive NPs are determiner
phrases Amys gt poss(e10,a,x) Predeterminer
all(e9, s, ...e1) (relation between set and
description) IN THIS ORDER
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Pronouns and Proper Nouns
It should be easy No internal structure
NP --gt Pronoun (PP)
I, you, he, she, anyone, one, ... NP --gt
ProperNoun (NNP, NNPS) Uruzgun Valley,
Enceladus But proper nouns sometimes function as
nouns inside NPs, rather than full
NPs The Voyager 2 spacecraft The
Cassini mission A resurgent Taliban So
maybe its better to treat proper nouns as simply
nouns Noun --gt ProperNoun where in most
uses it has no modifiers.
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Headless NPs
With some determiners, you dont need a head
noun I like those. I like
the. Give me some. Give me a.
You have many. I want my. I dont have
any. the most the
fifth-highest They can also occur with right
modifiers Those with siblings should stand
up for them. Many in America dont question
authority.

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Recognizing Noun Groups with Finite-State Automata
Noun groups can be recognized fairly reliably
with a finite-state automaton
NG --gt (Detp) (Adjs) Ns Detpcomplete Pro
Ntime that Nsing Detpcomplete --gt
( Advpre-num another det Proposs
( only (other) ) ) Number Q Q-er
(the) Q-est another Detcomplete,that
Proposs,complete Detpincomplete --gt
Det Proposs only a Detincomplete
Proposs,incomplete (other) Detpcomplete
other Adjs --gt Adj ( ( , and , and
) Adj ) Adj --gt JJ VBN VBG Number -
Nmeasure (- JJ) N - VBN Ns --gt (
JJ - ) Nsing,time,proper N
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Logical Form of Noun Groups
Nouns convey three kinds of information
Singular nouns man the entity referred
to man(x) the property
conveyed about that entity man(e,x) Plural
nouns men the set s referred to
the typical entity in that set x A
representation for men man(e,x)
plural(x,s) s is the set of men x
is the typical man e is the property of
xs being a man tall presidents gt tall(x)
president(e,x) plural(x,s) numerous
presidents gt numerous(s) president(e,x)
plural(x,s) former presidents gt former(e)
president(e,x) plural(x,s) the men ran gt
run(x) the men gathered gt gather(s)

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Logical Form of Noun Groups
Determiners and quantifiers are complicated in
their logical form. Standard approach
all, every gt (forall (x) ...) some,
a gt (exists (x) ...) the, these, such,
.... gt ? I would just say which of x, s, and e
the words meaning depends on. many men gt
many(s) the man gt the(x,e) x can be
identified by the description e such men
gt such(x,e) Possessives Pats book gt
Pat(x) Poss(x,y) book(y) Headless NPs
several arrived gt several(s) plural(x,s)
arrive(x) Verbal forms in adjective position
running man gt run(x) man(x) broken
window gt break(y,x) window(x)

Note object position
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Logical Form of Noun Groups
Verbal forms in adjective position running
man gt run(x) man(x) broken window gt
break(y,x) window(x) Possible positions for
present participle Adjective supporting
strike gt support(x,y) strike(x)
Prenominal noun parking space gt park(e,y,z)
nn(e,x) space(x) Head noun a brutal
shooting gt brutal(e) shoot(e,x,y) Three
types of adjectives (wrt logical form)
Standard red car gt red(x) car(x)
Opaque accidental guerilla gt accidental(e)
guerilla(e,x) (The person is not
accidental, only the property of being a
guerilla) Noun-like Saturnian system gt
Saturn(x) nn(x,y) system(y)
Note object position

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Attributives
Some attributive adjectives have an implicit
comparison set or scale A small elephant
is bigger than a big mosquito. That
mosquito is big. mosquito(x) big(x, s)
The implicit comparison set or scale, which must
be determined from context
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Proper Names
Proper names Could treat them as
constants Springfield is the capital
of Illinois. gt capital(Springfield,
Illinois) But there are many Springfields
we could treat it as a predicate true
of any town named Springfield
capital(x,y) Springfield(x) Illinois(y)
Or we could treat the name as a string, related
to the entity by the predicate name
capital(x,y) name(Springfield,
x) name(Illinois, y)
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Indexicals
An indexical or deictic is a word or phrase that
requires knowledge of the situation of
utterance for its interpretation. I,
you, we, here, now, some uses of this,
that, ... The property of being I is being
the speaker of the current utterance Indexicals
require an argument for the utterance or the
speech situation. I(x,u) x is the speaker of
utterance u you(x,u) x is the intended hearer
of utterance u we(s,u) s is a set of people
containing the speaker of utterance u here(x,u)
x is the place of utterance u now(t,u) t is the
time of utterance u ago(t,d,u) t is a duration
of d before the time of the utterance u Chris
said, I see you now. gt say(Chris,u)
content(e,u) see(e,x,y) I(x,u) you(y,u)
atTime(e,t) now(t,u)
from the quotation marks
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Quantifier Ambiguities
Every man loves a woman. gt (? m)(? w)
love(m,w) i.e., his
wife gt (? w)(? m) love(m,w)
i.e., Britney Spears Most politicians
in most countries can fool most of the people on
most issues most of the time. This has 120
possible readings, all distinct. e.g.,
different issues for each country, or same
issues? different people for each
issue, or same people? Do we need to generate
each separate reading? Quasi-logical form
(Alshawi), typical elements (me) Specify
the predicate-argument relations, remain silent
about quantifier scoping every(m,e1)
man(e1,m) love(m,w) a(w,e2)
woman(e2,w) May later learn
FunctionallyDependent(w,m) i.e., (? m)(?
w)
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Right Modifiers or Noun Complements
Anything that can be a predicate complement can
be a right modifier PP the man in the
black coat Adjective phrase the people
responsible, investors nationwide Past
participle the ingredients required for the
recipe Present participle those people
seeking reelection NP (Appositive) Barack
Obama, president of the U.S. Think of these
as reduced relatives the man (who is) in the
black coat Also relative clauses the
birds that I am able to identify () And a few
other, less common constructions
Infinitival complements an attempt to escape
Sentential complements the belief that
America deserves better
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Prepositional Phrases
Some examples a vital part of CalPERS
efforts the Cassini mission to
Saturn a ferocious fire fight with the
Taliban a cautionary tale about fights
breaking out the regularity of chunks over
different sentences PP attachment ambiguities
are the biggest source of ambiguity in English
I saw the whales in the bay with
binoculars. I saw the whales in the bay
with binoculars. etc. Usually attachments
dont cross Specify the length, in bytes,
of the word. Lots of ambiguities are benign
I never spent enough time in one place.
build a life for myself away from the job.
bear little resemblance to the usual phrase
structure.
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Adjective and Participle Phrases
Some examples big investors nationwide
the interest generated by Voyagers visit
A classic ambiguity in computational
linguistics I saw the Grand Canyon, flying
to New York.
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Appositive NPs
Proper names can be the head, or the
appositive.
Some examples Anne Stausboll, a 10-year
fund veteran, the Australian
counterinsurgency expert David Kilcullen a
term, accidental guerilla chunking
recognizing higher level units of structure
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Logical Forms of Right Modifiers
PP the cat in the hat gt cat(x) in(x,y)
hat(y) Sometimes arguments in relation
nouns mother of Pat gt mother(x,y)
Pat(y) Adjective phrase the man responsible
gt man(x) responsible(x,y) Past participle
the window broken by the boy gt window(x)
break(y,x) boy(y) Present participle a student
studying logic gt student(x) study(x,y)
logic(y) Appositives NP NP Barack Obama,
president of the U.S. Use the predicate be
Obama(x) be(x,y) president(y,z) US(z) or
identity of variables Obama(x)
president(x,z) US(z) or predicate Appos
Obama(x) Appos(x,y) president(y,z) US(z)
Appos usually means be, but can mean other
things
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Some Other Right Modifiers
Not an appositive because summit / last
March More like a PP
Time NPs the summit last March gt
atTime(s,t) Infinitival complements the
desire to fly gt desire(x,e)
fly(e,x) That clause the belief that
the world is round gt belief(x,e) round(e,y)
world(y)
Like an appositive because belief that the
world is round
Not a relative clause because nothings missing
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Relative Clauses
One of the arguments or adjuncts is missing from
the relative clause the relative clause is a
right adjunct on some head noun that head noun
supplies the missing argument or adjunct.
Simplest and most common case the subject is
missing fund which ( ) has lost more than
a quarter of its value the most momentous
thing that ( ) had happened in their valley
storms that ( ) set the sky close to the
ground images that ( ) confounded
planetary scientists
the gap
the filler
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Relative Clauses
Relative clauses in which the direct object or
some other complement is missing the man I
saw ( ) some form of chunked representation of
sentences, which we might
interpret ( ) as a phrase structure tree
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Relative Clauses
Relative clauses in which an adjunct is
missing beliefs for which our forbears fought
( ) ways to turn these villagers into allies (
) one way to capture the regularity of chunks
( )
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Why Long-DistanceDependencies?
NP
SBAR
NP
S
IN
VP
NP
S
V
VP
NP
S
V
VP
NP
NP
V
the book that Chris thinks
Pat said Kim read ()
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Other Long-Distance Dependencies
Relative clauses are examples of long-distance
dependencies, because the gap and its filler
can be arbitrarily far apart in the parse tree.
the man that Mary believes John asked Susan to
tell George to meet with ( )
To get the right logical form, we have to pass
information about the gap up to the filler (or
pass information about the filler down to the
gap).
Other long-distance dependency constructions Ques
tions Who does Mary believe John asked George
to meet with ( )? Wh-nominalizations Whoever
Mary believes John asked George
to meet with ( ) is here
what was most revealing about the battle was
the fact that ... asked later why
theyd done so the question of how to
learn structure from unannotated textual input
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Introducing Gaps in Clauses
The elegant way NPgapx --gt The
efficient way VPgapx --gt Vcompl1np
Sgapx --gt VP Passing gaps up to higher
nodes Sgapx --gt NP VPgapx
VPgapx --gt V NP (that) Sgapx These
work for gaps in questions and wh-nominalizations
too.
x is some identifier of the node that is gapped
Gives us a gap in the object
Gives us a gap in the subject
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Filling the Gaps
The wh-phrase introducing the relative clause
can be quite complex the man who I met (
) the man the brother of whose father I met
( )
Rule Replace the wh-word with the head
noun. Fill the gap with the whole wh-phrase
Similar rules for questions and wh-nominalizations
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Logical Forms for Long-DistanceDependencies
the man who arrived gt man(x) arrive(x) the
man whom Pat met gt man(x) Pat(y)
meet(y,x) the man for whom Pat works gt man(x)
Pat(y) work(e,y) for(e,x) the man whose
cousin arrived gt man(x) cousin(y,x)
arrive(y) whoever studies will pass gt
study(x) pass(e,x) Future(e)