Outline Lexical semantics and context Context Sentence semantics Verb as a predicate Semantics II: logical representation, from sentence to discourse Karel Pala, Zuzana Nevěřilová, Vojtěch Kovář Natural Language Processing Centre Faculty of Informatics, Masaryk University Botanická 68a, 602 00 Brno {pala, xpopelk, xkovar3}@fi.muni.cz PA153 Natural Language Processing Karel Pala, Zuzana Nevěřilová, Vojtěch Kovář FI MU Brno Semantics II: logical representation, from sentence to discourse Outline Lexical semantics and context Context Sentence semantics Verb as a predicate Outline 1 Lexical semantics and context 2 Context 3 Sentence semantics 4 Verb as a predicate Karel Pala, Zuzana Nevěřilová, Vojtěch Kovář FI MU Brno Semantics II: logical representation, from sentence to discourse Outline Lexical semantics and context Context Sentence semantics Verb as a predicate Lexical meaning and context Lexical meaning (lexical semantics) meaning of isolated words Autosemantic lexical units they carry meaning nouns, adjectives, verbs, adverbs black, high, run, let, actually (but e.g. “high school”) Synsemantic lexical units have meaning only in combination with autosemantics from, why, how, the Karel Pala, Zuzana Nevěřilová, Vojtěch Kovář FI MU Brno Semantics II: logical representation, from sentence to discourse Outline Lexical semantics and context Context Sentence semantics Verb as a predicate Lexical meaning and context Krakutel z jejich mrusy se ploc blutkal, načež potom tražil také všechny své stěvače. Vyšetřovatel jopuz hrych vlády tre moc naštval, bruvěž slekym rozzuřil vičké kruky moré posluchače. Vyšetřovatel z jejich vlády se moc naštval, načež potom rozzuřil také všechny své posluchače. Karel Pala, Zuzana Nevěřilová, Vojtěch Kovář FI MU Brno Semantics II: logical representation, from sentence to discourse Outline Lexical semantics and context Context Sentence semantics Verb as a predicate Context Verbal context previous/following words, sentences, ... Situation context place, time number of communication partners and their relationships knowledge of communication partners righarrow communication situation Social context education of the audience, status of the social group “what the f*ck are you doing here?” Karel Pala, Zuzana Nevěřilová, Vojtěch Kovář FI MU Brno Semantics II: logical representation, from sentence to discourse Outline Lexical semantics and context Context Sentence semantics Verb as a predicate Verbal context: Corpora concordance lines (small corpora) word sketch (large corpora) “sketch grammar” + statistics Karel Pala, Zuzana Nevěřilová, Vojtěch Kovář FI MU Brno Semantics II: logical representation, from sentence to discourse Outline Lexical semantics and context Context Sentence semantics Verb as a predicate Sentence semantics Meaning of a sentence meaning of the words + syntactic relationships between them Compositionality principle The meaning of the whole is a function of the meaning of the parts and the mode of combining them. The meaning of a complex expression is uniquely determined by the meaning of its constituents and the syntactic construction used to combine them. Karel Pala, Zuzana Nevěřilová, Vojtěch Kovář FI MU Brno Semantics II: logical representation, from sentence to discourse Outline Lexical semantics and context Context Sentence semantics Verb as a predicate Logical analysis of the sentence Sentence → logical formula predicate structure for verbs propositions have truth value (true, false) Propositions information content of the sentence in a certain context different sentences can lead to the same proposition “The Earth is round.” “The Earth has a round shape.” “Země je kulatá.” Karel Pala, Zuzana Nevěřilová, Vojtěch Kovář FI MU Brno Semantics II: logical representation, from sentence to discourse Outline Lexical semantics and context Context Sentence semantics Verb as a predicate First order predicate logic “Those who do not know statistics, will be classified F” ∀x : ¬knows(x, ”statistics”) ⇒ classif (x, ”F”) “Peter does not know statistics” ¬knows(”Peter”, ”statistics”) We can deduce classif (”Petr”, ”F”) “Peter is classified F.” Karel Pala, Zuzana Nevěřilová, Vojtěch Kovář FI MU Brno Semantics II: logical representation, from sentence to discourse Outline Lexical semantics and context Context Sentence semantics Verb as a predicate First order predicate logic Komu se nelení, tomu se zelení. Honza se odrazil od podlahy a vyskočil do dvou metrů. Tahle vláda není ani ryba ani rak. Karel Pala, Zuzana Nevěřilová, Vojtěch Kovář FI MU Brno Semantics II: logical representation, from sentence to discourse Outline Lexical semantics and context Context Sentence semantics Verb as a predicate First order predicate logic Komu se nelení, tomu se zelení. ∀x : N(x) ⇒ Z(x) Honza se odrazil od podlahy a vyskočil do dvou metrů. Tahle vláda není ani ryba ani rak. Karel Pala, Zuzana Nevěřilová, Vojtěch Kovář FI MU Brno Semantics II: logical representation, from sentence to discourse Outline Lexical semantics and context Context Sentence semantics Verb as a predicate First order predicate logic Komu se nelení, tomu se zelení. ∀x : N(x) ⇒ Z(x) Honza se odrazil od podlahy a vyskočil do dvou metrů. O(”Honza”, ”podlaha”) V (”Honza”, ”2 metry”) Tahle vláda není ani ryba ani rak. Karel Pala, Zuzana Nevěřilová, Vojtěch Kovář FI MU Brno Semantics II: logical representation, from sentence to discourse Outline Lexical semantics and context Context Sentence semantics Verb as a predicate First order predicate logic Komu se nelení, tomu se zelení. ∀x : N(x) ⇒ Z(x) Honza se odrazil od podlahy a vyskočil do dvou metrů. O(”Honza”, ”podlaha”) V (”Honza”, ”2 metry”) Tahle vláda není ani ryba ani rak. ¬("tahle vláda"="ryba") ∧ ¬("tahle vláda"="rak") Karel Pala, Zuzana Nevěřilová, Vojtěch Kovář FI MU Brno Semantics II: logical representation, from sentence to discourse Outline Lexical semantics and context Context Sentence semantics Verb as a predicate First order predicate logic: limits Some things are not propositions Good morning. Thank you If only I had money... Some propositions are not first order All people have some common features. ∃F∀x : F(x) More quantifiers somebody big part of many people Karel Pala, Zuzana Nevěřilová, Vojtěch Kovář FI MU Brno Semantics II: logical representation, from sentence to discourse Outline Lexical semantics and context Context Sentence semantics Verb as a predicate First order predicate logic: limits Types of arguments Peter lived on the first floor. Peter stil lived on Sunday → logic formalisms with types Karel Pala, Zuzana Nevěřilová, Vojtěch Kovář FI MU Brno Semantics II: logical representation, from sentence to discourse Outline Lexical semantics and context Context Sentence semantics Verb as a predicate Verb as a predicate Verb = predicate other sentence parts = arguments → verb valencies Break: AG(person) ART(product) INS(instrument) A boy break a window by a stone. The window was broken. A stone broke the window. A boy broke the window. Karel Pala, Zuzana Nevěřilová, Vojtěch Kovář FI MU Brno Semantics II: logical representation, from sentence to discourse Outline Lexical semantics and context Context Sentence semantics Verb as a predicate Verb valency lexicons VALLEX (Czech) Institute of Formal and Applied Linguistics 2,730 entries, 6,460 senses VerbaLex (Czech) Natural Language Processing Centre at FI 10,469 lemmas, 21,032 senses (literals) VerbNet (English) University of Colorado (Martha Palmer) 8,537 verbs Karel Pala, Zuzana Nevěřilová, Vojtěch Kovář FI MU Brno Semantics II: logical representation, from sentence to discourse Outline Lexical semantics and context Context Sentence semantics Verb as a predicate VALLEX Karel Pala, Zuzana Nevěřilová, Vojtěch Kovář FI MU Brno Semantics II: logical representation, from sentence to discourse Outline Lexical semantics and context Context Sentence semantics Verb as a predicate VerbaLex Karel Pala, Zuzana Nevěřilová, Vojtěch Kovář FI MU Brno Semantics II: logical representation, from sentence to discourse Outline Lexical semantics and context Context Sentence semantics Verb as a predicate VerbNet Karel Pala, Zuzana Nevěřilová, Vojtěch Kovář FI MU Brno Semantics II: logical representation, from sentence to discourse Outline Lexical semantics and context Context Sentence semantics Verb as a predicate Meaning in the valency frame verb + synonyms = synset (synonymical set) translation verb class (communicate, destroy) based on Palmer’s work sub-frames: the particular frames for the words from the synset syntactic information: number and order of arguments, cases, prepositions semantic roles + selectional preferences Karel Pala, Zuzana Nevěřilová, Vojtěch Kovář FI MU Brno Semantics II: logical representation, from sentence to discourse Outline Lexical semantics and context Context Sentence semantics Verb as a predicate Framenet lexicon of general valency frames interconnection of frames Karel Pala, Zuzana Nevěřilová, Vojtěch Kovář FI MU Brno Semantics II: logical representation, from sentence to discourse Outline Lexical semantics and context Context Sentence semantics Verb as a predicate FrameNet Karel Pala, Zuzana Nevěřilová, Vojtěch Kovář FI MU Brno Semantics II: logical representation, from sentence to discourse Outline Lexical semantics and context Context Sentence semantics Verb as a predicate References Mendelson, E. (1997). Introduction to Mathematical Logic. Discrete Mathematics and Its Applications Series. Chapman & Hall. Wu, Z. and Palmer, M. (1994). Verbs semantics and lexical selection. In Proceedings of the 32nd annual meeting on Association for Computational Linguistics, ACL ’94, pages 133–138, Stroudsburg, PA, USA. Association for Computational Linguistics. Karel Pala, Zuzana Nevěřilová, Vojtěch Kovář FI MU Brno Semantics II: logical representation, from sentence to discourse