Verb Net A ClassBased Verb Lexicon Presentation of

Verb. Net A Class-Based Verb Lexicon Presentation of Magdalena Leshtanska

Verb. Net Martha Palmer http: //verbs. colorado. edu/~mpalmer/projects/verbnet. html

Overview n n n Verb. Net – basic idea The Levin Verb Classification - overview, drawbacks, refinement Verb. Net Classes – LTAG Examples References

The Levin Verb Classification Beth Levin. 1993. English Verb Classes and Alternation, A Preliminary Investigation. The University of Chicago Press.

Example – break and cut n Transitive construction n Glass breaks easily. This loaf cuts easily. Simple intransitive construction n n John cut the bread. Middle construction n n John broke the window. The window broke. *The bread cut describes actions directed at achieving the goal of separating an object into pieces. break can‘t occur in the conative, cause it only specifies a resulting change of state – an object is separated into pieces If state is unchanged, no breaking actions are recognized.

The Levin Verb Classification n n n Israelul a lovit o bază militară aeriană în nord-vestul Siriei Băsescu îşi mută privirea asupra copilului şi îl loveşte pe acesta cu dosul palmei peste faţă. O maşină a Ambasadei României la Sofia a lovit mortal un bulgar. Doi paparazzi, retinuti dupa ce au lovit doi cameramani langa localul nuntii lui Tariceanu. Bilantul furtunii “Christian” care a lovit vestul si nordul Europei. În prima repriză, portughezul a şutat puternic o minge spre lateral, iar balonul a lovit o fetiţă din tribune.

The Levin Verb Classification n Mă gândesc să mănânc ceva. n La ce se pot gândi 3 fete când găsesc un trandafir. n Din punctul meu de vedere, m-aş gândi la o comisie specială. n n n Adică nu poţi să te gândeşti la ce nu vrei să te gândeşti fără să te gândeşti la asta. Când vom termina procesul de restituire poate putem gândi un sistem de finanţare autonom pentru biserici. O carte din care înveţi să fii mereu cu un pas înainte, să gândeşti înainte de a vorbi, să negociezi. Caută să fii matur(ă) înainte de a te gândi la căsătorie. Poate se va gândi cineva şi la potenţialul cercetării ştiinţifice româneşti.

The Levin Verb Classification n Approaches towards forming verb classes (Levin 1993) Predict syntax, using semantic information I can buy a house vs *I can think a house n Predict semantics, using syntactic information to hit someone vs to hit on someone n n n Assumes the sets of syntactic frames a verb can appear in reflect underlying semantic components that constrain allowable arguments Classes are based on the (in)ability of a verb to occur in pairs of meaning preserving syntactic frames (diathesis

The Levin Verb Classification - Drawbacks n n Inconsistencies – verbs can exist in multiple lists, sometimes with conflicting structure Levin explicitly states the syntax for each class, but falls short of assigning semantic components to each. And syntax alone is not enough: n n n John left the ball on the field (gave away) John left the field (went out) But: John left a fortune (gave away)

Levin Classes - Refinement (Dang 1998) n Intersective Levin classes n n If more than 3 members from intersected classes overlap, they‘re moved to a subcalss of their own Result: a fine-grained version, suitable for applications

Verb. Net - overview n n Largest online verb lexicon for English Hierarchical structure of intersected Levin verb classes LTAG formalism captures syntax for each verb class and assigns semantic predicates Links to other lexical resources e. g. Word. Net

Verb. Net - overview Table 1: Summary of the Lexicon's Extension First-level classes Thematic roles Original VN 191 21 Extended VN 274 23 Semantic predicates Syntactic restrictions (on sentential compl) Number of verb senses 64 94 3 55 4656 5257 3445 3769 Number of lemmas

Verb. Net Classes n Hierarchically organized n n n Class members share features a verb or subclass inherits features from the parent and may add more information Capture both syntax and semantics n n Thematic roles - Agent, Theme, Location, . . Syntactic frames. Each frame has selectional restrictions for the arguments in it – e. g. the agent of „run“ should be animate n semantic predicates with a time function n

Verb. Net Classes http: //verbs. colorado. edu/verb-index/vn/class-h. php

Verb. Net Classes 109 classes Putting Ingesting Removing Creation and transformation Sending and carrying Perception Psychological state Change of possession Social interaction Hold and keep Sound made by animals Killing Throwing Contact by impact Appearance and disappearance Communication Contact by impact Body related Aspect (start, stop) Combining and attaching Motion Relating and correlating Measure Lingering and rushing Separating and disassembling Change of state Emission (sound, smell). . .

Verb. Net Syntactic Frames n Come as an ordered sequence of thematic roles n n John hit the ball - Agent V Patient John hit at the window - Agent V at Patient John hit the sticks together – Agent V Patient[+plural] together Adorned with a conjunction of semantic predicates. n Semantic predicates can be n n General (e. g. cause, motion) Specific (e. g. , suffocate) Variable (Prep) Each predicate includes a time function showing at what stage in the event it holds: start, during, end, result

Verb. Net Syntactic Frames examples begin-55. 1

Verb. Net Syntactic Frames examples characterize-29. 2

Verb. Net Syntactic Frames examples eat-39. 1 -1

Verb. Net Syntactic Frames examples entity_specific_modes_being-47. 2

Actor: Agent: Asset: Attribute: Verb. Net Thematic Roles 23 roles Beneficiary: Cause: Location, Destination, Source: Destination: Source: Location: Experiencer: Extent: Instrument: Material and Product: Material: Product: Patient: Predicate: Recipient: Stimulus: Theme: Time: Topic:

Verb. Net Selectional Restrictions: semantic classes exchange-13. 6

Verb. Net Selectional Restrictions: semantic classes hurt-40. 8. 3

Verb. Net Selectional Restrictions: semantic classes wink-40. 3. 1

Verb. Net Selectional Restrictions: semantic classes

Verb. Net Classes – LTAG Lexicalized Tree-Adjoining Grammar n n Classes modelled by LTAG (Lexicalized Tree-Adjoining Grammar) LTAG allows to n n generate syntactic variants, e. g. passive from declarative incorporate semantics into the model

LTAG - Run

LTAG - Hit

Members, Roles & Class Hierarchy

Syntactic Frames – Hit 18. 1 Frames Example Syntax Basic Transitive "He hit the ball. " Agent V Patient NP-PP Instrument-PP "He hit the ball with a stick. " Agent V Patient {with} Instrument Together Reciprocal Alternation Transitive "He hit the sticks together. " NP-ADJP Resultative "He kicked the door open. " NP-ADJP-PP Resultative, Instrument-PP "He hit the door open with his foot. " Agent V Patient <+plural> (together) Agent V Patient ADJ {with} Instrument "He hit the window to pieces. " Agent V Patient {to into} Oblique [+state] NP-PP-PP Result-PP, Instrument-PP "He hit the window to pieces with a club. " Agent V Patient {to into} Oblique [+state] {with} Instrument Conative "He hit at the window. " Agent V (at) Patient Conative "He hit at the window with an open hand. " Agent V (at) Patient {with} Instrument NP-PP "He hit the stick against/on the fence. " Agent V Instrument {against on} Patient Instrument Subject Alternation "The stick hit the fence. " NP-ADJP Resultative "The stick hit the door open. " Instrument V Patient ADJ "The club hit the window to pieces. " Instrument V Patient {to into} Oblique [+state] NP-PP Result-PP NP-ADJP Result-PP Instrument V Patient

…Semantic representation

References n n Hoa Trang Dang, Karin Kipper, Martha Palmer and J. Rosenzweig. 1998 “Investigating Regular Sense Extensions Based on Intersective Levin Classes”. In Proceedings of Coling-ACL 98. Montreal, CA. Hoa Trang Dang, Karin Kipper, and Martha Palmer 2000. Integrating compositional semantics into a verb lexicon. In Proceedings of the Eighteenth International Conference on Computational Linguistics COLING- 000), Saarbrücken, Germany, July- August. Karin Kipper, Hoa Trang Dang, and Martha Palmer. 2000 a. Class-based construction of a verb lexicon. In Proceedings of the Seventh National Conference on Artificial Intelligence (AAAI-2000), Austin, TX, July. August. Beth Levin. 1993. English Verb Classes and Alternation, A Preliminary Investigation. The University of Chicago Press.