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Analyzing Features of Grammatical Categories Show my head to the people; it is worth seeing. --Feature structure, to Ivan Sag in a dream
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CFG’s: Chock Full of Goofs Requires massively redundant rules Fails to capture generalizations S →NP-3p-sg VP-3p-sg S →NP-3p-pl VP-3p-pl S →NP1 VP1 S →NP2 VP2 Rules are arbitrary S →NP1 VP2
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HPSG: How to Phix Subpar cfGs Change atomic categories into categories that can be decomposed into features.
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Let’s get our terms straight university NAMEStanford Univ. FOUNDERS PRESIDENT TEL feature structure type featurevalue
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More complex structures Embedding, see p. 54, fig.7a Indexes Department TEL [1] 650-723-4284 CHAIR [TEL [1] ]
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HPSG Types and Features Initial type hierarchy, p. 61, fig. 25
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HPSG Types and Features Initial type hierarchy, p. 61, fig. 25 First important subtypes divide expressions into words and phrases
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HPSG Types and Features Initial type hierarchy, p. 61, fig. 25 First important subtypes divide expressions into words and phrases All expressions have the feature HEAD
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HPSG Types and Features Initial type hierarchy, p. 61, fig. 25 First important subtypes divide expressions into words and phrases All expressions have the feature HEAD with a value from the pos types
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HPSG Types and Features Initial type hierarchy, p. 61, fig. 25 First important subtypes divide expressions into words and phrases All expressions have the feature HEAD with a value from the pos types
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Agreement Some pos types exhibit agreement, so we group them into their own subtype agr-pos, which carries the feature AGR AGR feature takes the value agr-cat, which is a sub-type of feature-structure It has (at least) the features PER and NUM PER takes the values {1 st,2 nd,3 rd } NUM takes the values {sg, pl} See p. 70, fig. 49
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How much of this is universal? Other languages have different values? All languages have all features and values, but optimality-like constraints ensure that only some show up?
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The VAL feature A feature of expressions
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The VAL feature A feature of expressions Takes the value val-cat, which has the features COMPS and SPR
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The VAL feature A feature of expressions Takes the value val-cat, which has the features COMPS and SPR These “represent the combinatoric potential of the word or phrase”
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The VAL feature A feature of expressions Takes the value val-cat, which has the features COMPS and SPR These “represent the combinatoric potential of the word or phrase” COMPS takes the value itr, str, or dtr; p.62, fig. 27 All expressions have this feature (so far)
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Underspecification A type can be unspecified for a particular feature This picks out a larger class of feature structures (it includes more kinds of feature structures) Underspecification allows some kinds of generalizations that we couldn’t get from CFGs, p. 63, fig.28
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The SPR feature A generalization of the notion ‘determiner’ Distinguishes N, NOM, and NP SPR + for NP SPR – for NOM
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The SPR feature A generalization of the notion ‘determiner’ Distinguishes N, NOM, and NP SPR + for NP SPR – for NOM SPR + or SPR – for N
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The SPR feature A generalization of the notion ‘determiner’ Distinguishes N, NOM, and NP SPR + for NP SPR – for NOM SPR + or SPR – for N Also used to distinguish S and VP S is SPR + VP needs a subject NP to the left, so it is SPR – Huh? p. 64, fig. 34
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Diagramming for Dollars
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Team 1: lexical entry for the noun “verb” As in, “Weird can be a verb” Team 2: lexical entry for the verb “verbs” As in, “Calvin verbs the word ‘weird’.”
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Diagramming for Dollars Round 1: lexical entries Round 2: p. 65, fig. 37a
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Diagramming for Dollars Round 1: lexical entries Round 2: p. 65, fig. 37a Round 3: p. 69, fig. 47
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Agreement Rule Agreement features get “passed up” from daughters to mothers See rule, p. 70, fig. 50 Tree in 51
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Head Feature Principle There is a wisdom of the head… --Charles Dickens Every headed phrase has a head daughter with the same head values General form: p. 72, fig. 53 Headed rules: p. 73, fig. 54, esp. 54d
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Diagramming for Dollars Round 1: lexical entries Round 2: p. 65, fig. 37a Round 3: p. 69, fig. 47 Round 4: “LING7420 loves HPSG.” “The professor cheers.”
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