CS 544: Lecture 3.3 Syntax and Compositional Semantics

CS 544: Lecture 3.3Syntax and Compositional Semantics Jerry R. Hobbs USC/ISI Marina del Rey, CA

Lexicon and Syntax S Syntax tells us identity of arguments x1=x2 NP VP John works. john’(e1,x1) work’(e2,x2) & Present’(e3,e2) The lexicon gives us the predicates, one for each word/morpheme Syntax is how we get predicate-argument structure out of concatenation e1 is the property of x1 being John e2 is the event of x2 working e3 is the property of e2 being in the present

All the Syntax of English (almost) Structure of the clause Structure of the noun phrase Adverbials Relative clauses and other long-distance dependencies Conjunctions (or Coordination)

Structure of the Clause The basic clause consists of a Subject, a Verb, and zero, one or two Complements. Chris sleeps. Chris helps Pat. Chris gave Pat a book. The Complements can be NPs, PPs, AdjPs or clauses, e.g., PP: Chris relies onPat. AdjP: Chris is acting foolish. Infinitive: Chris wants to fly. Chris wants Pat to fly. Full declarative clause: Chris knows that he can’t fly. Gerunds: Chris likes seeing movies. Small clauses: Pat considers Chris foolish. Sometimes the subject of the main clause becomes the subject of the complement as well. Chris wants to fly ==> want’(e1,C,e2) & fly’(e2,C) (Subject Control) Subcategorization is the specification for each verb of the kinds of complements it can take: want: NP, Infinitive, NP Infinitive

Auxilliaries Auxilliaries are subject control verbs, subcategorized for the kind of VP that can follow them. It could have been fixed by now. VP could VP Modal, subcategorized for tenseless VP have VP “have” conveys Perfect; subcat VP[vbn] been VP “be” + VP[vbn] conveys passive; subject moves to object position fixed could’(e1,x,e2) & Perfect’(e2,e3) & fix’(e4,y,x)

Prepositions and AdjectivesAlso Subcategorize Prepositions: NP: in the room Declarative clause: Before the party was over, Chris left. Small clause: With the party dying down, Chris left. (subordinate conjunctions) Adjectives: Infinitive: able to fly “that” clause: certain that he could fly

Predicate Complements Complements of the verb “be”: NP: Chris is a computer scientist. be’(e,x,y) PP: Chris is in this building. in’(e,x,y) AdjP: Chris is able to ski. able’(e,x,e1) & ski’(e1,x) Present and past participles can appear anywhere adjectives can appear. Similarly, VP[vbg], VP[vbn] for AdjP VP[vbn]: Chris was given a book. (passive) VP[vbg]: Chris is reading the book. (progressive)

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: Amy’s => pos’(e10,a,x) Predeterminer: all’(e9, s, ...&e1) (relation between set and description) IN THIS ORDER

Some Ambiguities Often a word can be an adjective in the adjective position: criminal lawyer: a lawyer who is a criminal Or a noun in the prenominal noun position: criminal lawyer: a lawyer who bears some relation to criminals, i.e., defends them A present participle of a verb can appear in both places: a skiing man vs. a skiing lesson noun position: lesson w some relaion to skiing adjective position: a man who is skiing

The Structure of NPs: Right Modifiers Anything that can be a predicate complement can be the right modifier of a noun: NP: the artist Michelangelo; George Bush, president of the U.S. (appositives) PP: the man in the black coat, the party after Chris was elected AdjP: the people responsible for the damage VP[vbn]: the student given a present VP[vbg]: the people seeing the movie The head noun is the “subject” of the predicate. Also relative clauses: the people that Chris saw () yesterday. The head noun fills the gap. be’(e1,a,m) after’(e1,p,e2) responsible’(e1,p,d) give’(e1,x,s,p) see’(e1,p,m) see’(e1,c,p)

Structure of Adverbials read’(e2,c,b) Anything that can be a predicate complement can also be an adverbial: PP: Chris read the book in the library. AdjP: Chris read the book, enthusiastic about the subject. NP: Chris read the book, a real surprise to me. VP[vbn]: Chris read the book, based on what Pat told me. VP[vbg]: Chris read the book, wishing he didn’t have to. Also adverbs: Chris read the book quickly. Also relative clauses: Chris read the book, which surprised me. in’(e1,e2,l) enthusiastic’(e1,c,s) be’(e1,e2,s) base’(e1,x,e2,e3) wish’(e1,c,e3) quick’(e1,e2) surprise’(e1,e2,i)

Placement and Logical Formof Adverbials Adverbials can appear before, after or between any of the constituents of the structure it modifies. Quickly Chris read the book. Chris quickly read the book. Chris read quickly every book that was required. Chris read the book quickly. The “subject” of the adverbial is the eventuality associated with the S or VP it modifies: Chris read the book in the library. read’(e1,c,b) & in’(e2,e1,l) Chris read the book quickly. read’(e1,c,b) & quick’(e2,e1)

Argument or Adverbial? For PPs especially, it is often unclear whether it is and argument or adverbial: Pat will go from California to Japan. ==> go’(e,p,c,j) OR go’(e,p) & from’(e1,e,c) & to’(e2,e,j) In an inference system with the right rules, this distinction doesn’t matter: go3’(e,x,y,z) <--> go1’(e,x) & from’(e1,e,y) & to’(e2,e,z)

Long-Distance Dependencies(including wh-Constructions) filler gap Relative clauses, used as right modifiers of nouns (and Ss): Don’t bite the hand that () feeds you. Chris visited the town where he was born. Chris left early, which () surprised us. Wh-Questions: What did Chris see ()? Where did Chris say Pat went? Wh-Nominals, used in the same positions as NPs: Whatever you do () is okay with me. I don’t know what to do () or how to do it. “Tough movement” in complements of some adjectives: Chris is easy for anyone to talk to (). wh-phrase + yes-no question (with gap)

NP Why “Long-Distance”? NP SBAR IN S NP VP S V VP NP S V VP NP NP V the book that Chris thinks Pat said Kim read ()

Relation between the Filler and Gap The wh-phrase can fill an obligatory constituent in the relative clause: the student who () got the scholarship the student whom the professor saw () the student whom the dean said hello to () The wh-phrase can act as an optional adverbial on the relative clause: the child to whom I read the book the city where I was born Ambiguities more likely in latter case: the man to whom John said he sold the book ?

“Pied Piping” a man the brother of whom I have met () a system whoseconvenience consumers like () The wh-word is identical to the head noun. The whole wh-phrase fills the gap.

Coordination Coordinate conjunctions: and, or, but Conjunction constructions can be quite complicated, in general: Pat likes Chris, and Kim too. (ambiguous) Pat likes and wants to go on a date with Chris. The teacher likes intelligent and enthusiastic students. (ambiguous) The three tall English and two short Danish men John believes Mary likes him and is happy. (ambiguous) John likes Mary, and Pat Chris. Sudan is an underdeveloped country, the northern half of which is desert and the southern jungle. But .....

Coordination of Like Constituents The vast majority of coordination constructions conjoin like constituents: S and S: John likes Mary, and Chris likes Pat. VP CC VP: Chris likes Pat but hates Kim. VB CC VB: Everybody either loves or hates Hillary. NP and NP: Chris and Pat like Kim. NN and NN: the man and woman JJ and JJ: the tall and handsome man PP and PP: We went over the bridge and through the woods. IN and IN: Chris ran to and from school Predicate complements: Chris is rich, educated, and in the movie industry. JJ VBN PP

Logical Form of Conjunctions Two cases: Clause conjunction: Chris arrived and Pat left. arrive’(e1,c) & leave’(e2,p) & and’(e3,e1,e2) logical conjunction NP conjunction: Chris and Pat andn’(e,x,c,p) x is the typical element of the set {x,p} set construction “intelligent and enthusiastic students” is ambiguous: => students who are both intelligent and enthusiastic (Clause) => intelligent students and enthusiastic students (NP)

Summary of “Shallow” Logical Form The logical form of a sentence is an existentially quantified conjunction of propositions: “The teacher graded the papers slowly.” ==> (E e1,e2,e3,e4,e5,e6,e7,e8,t,p,s) [the’(e1,t,e2) & teacher’(e2,t) & grade’(e3,t,p) & Past’(e4,e3) & the’(e5,p,e6) & paper’(e6,p) & Plural’(e6,p,s) & slow’(e7,e3)] Nouns: book => book’(e,x) Proper nouns: Chris => Chris’(e,x) Plural nouns: books => book’(e1,x) & Plural’(e2,x,s) Prenominal nouns:wine glass=> wine’(e1,x) & nn’(e2,x,y) & glass’(e3,y) Adjectives: tall => tall’(e,x) Adjectives with complements: able to fly => able’(e1,x,e2) & fly’(e2,x) Determiners: the => the’(e1,x,e2) = x is uniquely identifiable in context by means of the property e2 Quantifiers: many => many’(e, s) (a property of the set) Numbers: three => three’(e,s) (a property of the set)

Summary of “Shallow” Logical Form Verbs: Intransitive: sleep => sleep’(e,x) Transitive: read => read’(e,x,y) Ditransitive: give => give’(e,x,y,z) Infinitive complemenet: want to go => want’(e1,x,e2) & go’(e2,x) Sentential complement: say that he left => say’(e1,x,e2) & Past’(e2,e3) & leave’(e3,y) Prepositions: P NP: in Tampa => in’(e,x,t) P S: before he left => before’(e1,x,e2) & Past’(e2,e3) & leave’(e3,y) (x argument (subject) is the S or NP the PP modifies) Adverbs: run quickly => quick’(e1,e2) & run’(e2,x)

Summary of “Shallow” Logical Form Conjunction: Clause conjunction: Chris arrived and Kim left => arrive’(e1,c) & leave’(e2,k) & and’(e3,e1,e2) NP conjunction: Chris and Pat => andn’(e1,x,c,p)

CS 544: Lecture 3.3 Syntax and Compositional Semantics