1. Default Inheritance in Constraint-based Frameworks Christof Rumpf Heinrich-Heine-Universität Düsseldorf June 24, 2010 http://www.phil-fak.uni- duesseldorf.de/~rumpf/talks/DefaultInheritance2.pdf

2. 24.06.2010Default Inheritance2 Overview motivation monotonic inheritance nonmonotonic unification nonmonotonic inheritance

3. 24.06.2010Default Inheritance3 Motivation for inheritance –compact representations (elimin. redundancies) –modelling of relations and generalizations for default inheritance –systematic modelling of regularities, subregularities, and irregularities

4. 24.06.2010Default Inheritance4 Tweety bird eaglepenguin can flycan not fly bird eaglepenguin can fly can not fly monotonic nonmonotonic no information at all conflict resolution necessary arbitrary alternants

5. Monotonic Inheritance in Constraint-based Frameworks PATR, ALE, CUF, QType,... GPSG, HPSG, LFG, UCG,...

6. 24.06.2010Default Inheritance6 Levels for Inheritance Mechanisms static type signature macros relational constraints type constraints lexical rules

7. 24.06.2010Default Inheritance7 Typical Static Type Signatures two sets: –types T –features F two relations: –immediate subtype T  T, azyclic –appropriateness, without polyfeatures a partial function F  T  T multiple inheritance of feature/value-pairs via subtype relation and unification no coindexation, since there are no variables in the description language finite description for infinite sets of objects (i.e. lists)

8. 24.06.2010Default Inheritance8 Inheritance in a Type Signature top > a, b, x, y < f:top. a > c < g:x. b > c < g:y, f:x. x > z. y > z. z < h:top. subtype appropriateness multiple inheritance

9. 24.06.2010Default Inheritance9 Feature Logic a feature logic is used to describe instances of the classes of objects defined in the type signature it usually includes –variables  coindexation –conjunction  unification –disjunction  nondeterminism –negation  nondeterminism Descr  2 FSs Descr  FSs

10. 24.06.2010Default Inheritance10 Macros are abbreviations for feature logic expressions can be named and create independent inheritance hierarchies do not add anything new to the signature can be used to refine and extend the classes of objects defined in the signature beyond the signature (creating new instances)

11. 24.06.2010Default Inheritance11 Relational Constraints define a general CLP language over feature logic expressions (definite clauses). are an extension of macros with recursion and, perhaps control operators like cut or negation by failure. might be used within type constraints. can not be computed offline in general.

12. 24.06.2010Default Inheritance12 Type Constraints they add information to the types in a static type signature their description language can be a feature logic incl. relational constraints –offline computability of the static type signature not guaranteed (append and other recursive operations)

13. 24.06.2010Default Inheritance13 Persistent Local Coindexation a < f:x, g:x. a constr f:Var & g:Var. token identity type identity subtype type constraint

14. 24.06.2010Default Inheritance14 Nonlocal Coindexation a constr f:Var & @true(b & h:Var). type constraint true(top) ::= top. relational constraint x y z top like a nonpersistent copying operation orthogonal?

15. 24.06.2010Default Inheritance15 Inheritance with Type Constraints type constraints –rely on the type hierarchy - they can not be named and therefore not build an additional hierarchy (like macros) –add information to the signature that is inherited top down with unification –can introduce a kind of ‚orthogonal‘ inheritance

16. Default Unification Bouma, Carpenter, Lascarides, Copestake, Briscoe,...

17. 24.06.2010Default Inheritance17 Credulous Default Unification nondefault default nondeterministic result Lascarides/Copestake 1999

18. 24.06.2010Default Inheritance18 Sceptical Default Unification nondefault default deterministic result Erjavec 1998 b?

19. 24.06.2010Default Inheritance19 Nonassoziative Operation Lascarides/Copestake 1999 nd d

20. 24.06.2010Default Inheritance20 Criteria for Default Unification Nondefault information is marked. DU can not fail. DU behaves like MU if there is no conflicting information. DU is deterministic. DU is commutative und associative. Defaults are ordered by specificity. Lascarides et al. 1996

21. 24.06.2010Default Inheritance21 Y et A nother D efault U nification (Lascarides/Copestake 1999)

22. 24.06.2010Default Inheritance22 YADU Inheritance (Lascarides/Copestake 1999)

23. Nonmonotonic Type Signatures Subrelex: Modelling Subregularities in the Lexikon (SFB 282 Project, 2000-2002) QType: A Grammar Developement Environment with Nonmonotonic Inheritance in the Type Signature

24. 24.06.2010Default Inheritance24 Subrelex Goals nonmonotonic, but declarative representations for regularities, subregularities und irregularities in a constraint-based framework tractable implementation formalize and implement empirical linguistic results of other SFB 282 projects (i.e. CB-LDG, Rumpf & Stiebels 1998) reconstruct relevant NL phenomena treated by the nonmonotonicity community

25. 24.06.2010Default Inheritance25 Subrelex Methods use of nonmonotonic inheritance in the type signature allow type constraints to enrich the expressive power of signatures transform nonmonotonic signatures to monotonic ones offline use monotonic signatures and monotonic unification at parsetime

26. 24.06.2010Default Inheritance26 Transformation of Nonmonotonic to Monotonic Signatures nonmonotonicmonotonic generalization of verb and pst-t-verb