Article Structure
Abstract
The standard set of rules defined in Combinatory Categorial Grammar (CCG) fails to provide satisfactory analyses for a number of syntactic structures found in natural languages.
Introduction
Combinatory Categorial Grammar (CCG, Steedman (2000)) is a compositional, semantically transparent formalism that is both linguistically expressive and computationally tractable.
Combinatory Categorial Grammar
CCG uses a universal set of syntactic rules based on the B, T, and S combinators of combinatory logic (Curry and Feys, 1958): (2) Br ((Bf)g)w = f(gw) T: T51: f = fa: SI ((Sf)g)w = fw(gw) CCG functors are functions over strings of symbols,
Linguistic Motivation for D
CCG is only partially associative.
Deriving Eisner Normal Form
Adding new rules can have implications for parsing efficiency.
Conclusion
Including the D-combinator rules in the CCG rule set lets us capture several linguistic generalizations that lack satisfactory analyses in standard CCG.
Topics
CCG
- The standard set of rules defined in Combinatory Categorial Grammar ( CCG ) fails to provide satisfactory analyses for a number of syntactic structures found in natural languages.Page 1, “Abstract”
- These structures can be analyzed elegantly by augmenting CCG with a class of rules based on the combinator D (Curry and Feys, 1958).Page 1, “Abstract”
- Combinatory Categorial Grammar ( CCG , Steedman (2000)) is a compositional, semantically transparent formalism that is both linguistically expressive and computationally tractable.Page 1, “Introduction”
- A distinctive aspect of CCG is that it provides a very flexible notion of constituency.Page 1, “Introduction”
- that even with its flexibility, CCG as standardly defined is not permissive enough for certain linguistic constructions and greater incrementality.Page 1, “Introduction”
- (1) X/(y/Z)If y/Wrg 2* X/(W/Z)=Ah-f(Aw-ghw) We show that CCG augmented with this rule improves CCG’s empirical coverage by allowing better analyses of modal verbs in English and causatives in Spanish, and certain coordinate constructions.Page 1, “Introduction”
- CCG uses a universal set of syntactic rules based on the B, T, and S combinators of combinatory logic (Curry and Feys, 1958): (2) Br ((Bf)g)w = f(gw) T: T51: f = fa: SI ((Sf)g)w = fw(gw) CCG functors are functions over strings of symbols,Page 1, “Combinatory Categorial Grammar”
- The rules of this multimodal version of CCG (Baldridge, 2002; Baldridge and Kruijff, 2003) are derived as theorems of a Categorial Type Logic (CTL, Moortgat (1997)).Page 2, “Combinatory Categorial Grammar”
- This treats CCG as a compilation of CTL proofs, providing a principled, grammar-internal basis for restrictions on the CCG rules, transferring language-particular restrictions on rule application to the lexicon, and allowing the CCG rules to be viewed as grammatical universals (Baldridge and Kruijff, 2003; Steedman and Baldridge, To Appear).Page 2, “Combinatory Categorial Grammar”
- In CCG , such constituents simply follow from the associativity added by the B and T rules.Page 2, “Combinatory Categorial Grammar”
- CCG’s approach is appealing because such constituents are not odd at all: they simply follow from the fact that CCG is a system of type-based grammatical inference that allows left associativity.Page 2, “Combinatory Categorial Grammar”
See all papers in Proc. ACL 2008 that mention CCG.
See all papers in Proc. ACL that mention CCG.
Back to top.
parse tree
- (30) For a set S of semantically equivalent2 parse trees for a string ABC, admit the unique parse tree such that at least one of (i) or (ii) holds:Page 5, “Deriving Eisner Normal Form”
- (31) Theorem 1 : For every parse tree oz, there is a semantically equivalent parse-tree N F(a) in which no node resulting from application of B or S functions as the primary functor in a rule application.Page 5, “Deriving Eisner Normal Form”
- (32) Theorem 2: If N F(a) and N F(o/ ) are distinct parse trees , then their model-theoretic interpretations are distinct.Page 5, “Deriving Eisner Normal Form”
- 2Two parse trees are semantically equivalent if: (i) their leaf nodes have equivalent interpretations, and (ii) equivalent scope relations hold between their respective leaf-node meanings.Page 5, “Deriving Eisner Normal Form”
- (35) Given a parse tree oz: i.Page 5, “Deriving Eisner Normal Form”
- If oz is a parse tree (R, B, 7) and NF(fl), NFW), then NF(a).Page 5, “Deriving Eisner Normal Form”
See all papers in Proc. ACL 2008 that mention parse tree.
See all papers in Proc. ACL that mention parse tree.
Back to top.
