tractable extensions of the description logic el with numerical datatypes

88
T RACTABLE E XTENSIONS OF THE DESCRIPTION L OGIC EL WITH NUMERICAL DATATYPES Despoina Magka , Yevgeny Kazakov and Ian Horrocks Oxford University Computing Laboratory July 16, 2010

Upload: despoina-magka

Post on 11-Jun-2015

613 views

Category:

Documents


2 download

DESCRIPTION

We consider extensions of the lightweight description logic (DL) EL with numerical datatypes such as naturals, integers, rationals and reals equipped with relations such as equality and inequalities. It is well-known that the main reasoning problems for such DLs are decid- able in polynomial time provided that the datatypes enjoy the so-called convexity property. Unfortunately many combinations of the numerical relations violate convexity, which makes the usage of these datatypes rather limited in practice. In this paper, we make a more fine-grained complexity analysis of these DLs by considering restrictions not only on the kinds of relations that can be used in ontologies but also on their occurrences, such as allowing certain relations to appear only on the left- hand side of the axioms. To this end, we introduce a notion of safety for a numerical datatype with restrictions (NDR) which guarantees tractabil- ity, extend the EL reasoning algorithm to these cases, and provide a complete classification of safe NDRs for natural numbers, integers, ra- tionals and reals.

TRANSCRIPT

Page 1: Tractable Extensions of the Description Logic EL with Numerical Datatypes

TRACTABLE EXTENSIONS OF THE DESCRIPTION

LOGIC EL WITH NUMERICAL DATATYPES

Despoina Magka, Yevgeny Kazakov and Ian Horrocks

Oxford University Computing Laboratory

July 16, 2010

Page 2: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Introduction

OUTLINE

1 INTRODUCTION

2 REASONING IN EL⊥(D)

3 CONCLUSION

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 2/20

Page 3: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Introduction

ONTOLOGIES

Ontologies are formal descriptions of domains such as:

Aerospace

Cellular biology

Human anatomy

Drugs

Applications:

Automated decision support

Reference databases

. . .

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 3/20

Page 4: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Introduction

ONTOLOGIES

Ontologies are formal descriptions of domains such as:

Aerospace

Cellular biology

Human anatomy

Drugs

Applications:

Automated decision support

Reference databases

. . .

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 3/20

Page 5: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Introduction

ONTOLOGIES

Ontologies are formal descriptions of domains such as:

Aerospace

Cellular biology

Human anatomy

Drugs

Applications:

Automated decision support

Reference databases

. . .

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 3/20

Page 6: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Introduction

ONTOLOGIES

Ontologies are formal descriptions of domains such as:

Aerospace

Cellular biology

Human anatomy

Drugs

Applications:

Automated decision support

Reference databases

. . .

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 3/20

Page 7: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Introduction

ONTOLOGIES

Ontologies are formal descriptions of domains such as:

Aerospace

Cellular biology

Human anatomy

Drugs

Applications:

Automated decision support

Reference databases

. . .

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 3/20

Page 8: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Introduction

ONTOLOGIES

Ontologies are formal descriptions of domains such as:

Aerospace

Cellular biology

Human anatomy

Drugs

Applications:

Automated decision support

Reference databases

. . .

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 3/20

Page 9: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Introduction

ONTOLOGIES

Ontologies are formal descriptions of domains such as:

Aerospace

Cellular biology

Human anatomy

Drugs

Applications:

Automated decision support

Reference databases

. . .

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 3/20

Page 10: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Introduction

ONTOLOGIES

Ontologies are formal descriptions of domains such as:

Aerospace

Cellular biology

Human anatomy

Drugs

Applications:

Automated decision support

Reference databases

. . .

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 3/20

Page 11: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Introduction

ONTOLOGIES

Ontologies are formal descriptions of domains such as:

Aerospace

Cellular biology

Human anatomy

Drugs

Applications:

Automated decision support

Reference databases

. . .

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 3/20

Page 12: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Introduction

ONTOLOGY AXIOMS

Terms describe entities from specific domains, e.g. for adrug ontology:

ParacetamolPatientA drug that contains 500 mg of paracetamol per tabletA patient who has age less than 6 years

Axioms formulate properties and restrictions using terms:

Panadol is a drug.Panadol contains paracetamol.Panadol contains 500 mg of paracetamol per tablet.[A patient who has age less than 6 years] should not beprescribed anything which [contains more than 250 mg ofparacetamol per tablet].

Restrictions specify ranges of data values:

500 mgmore than 250 mgless than 6 years

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 4/20

Page 13: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Introduction

ONTOLOGY AXIOMS

Terms describe entities from specific domains, e.g. for adrug ontology:

Paracetamol

PatientA drug that contains 500 mg of paracetamol per tabletA patient who has age less than 6 years

Axioms formulate properties and restrictions using terms:

Panadol is a drug.Panadol contains paracetamol.Panadol contains 500 mg of paracetamol per tablet.[A patient who has age less than 6 years] should not beprescribed anything which [contains more than 250 mg ofparacetamol per tablet].

Restrictions specify ranges of data values:

500 mgmore than 250 mgless than 6 years

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 4/20

Page 14: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Introduction

ONTOLOGY AXIOMS

Terms describe entities from specific domains, e.g. for adrug ontology:

ParacetamolPatient

A drug that contains 500 mg of paracetamol per tabletA patient who has age less than 6 years

Axioms formulate properties and restrictions using terms:

Panadol is a drug.Panadol contains paracetamol.Panadol contains 500 mg of paracetamol per tablet.[A patient who has age less than 6 years] should not beprescribed anything which [contains more than 250 mg ofparacetamol per tablet].

Restrictions specify ranges of data values:

500 mgmore than 250 mgless than 6 years

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 4/20

Page 15: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Introduction

ONTOLOGY AXIOMS

Terms describe entities from specific domains, e.g. for adrug ontology:

ParacetamolPatientA drug that contains 500 mg of paracetamol per tablet

A patient who has age less than 6 yearsAxioms formulate properties and restrictions using terms:

Panadol is a drug.Panadol contains paracetamol.Panadol contains 500 mg of paracetamol per tablet.[A patient who has age less than 6 years] should not beprescribed anything which [contains more than 250 mg ofparacetamol per tablet].

Restrictions specify ranges of data values:

500 mgmore than 250 mgless than 6 years

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 4/20

Page 16: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Introduction

ONTOLOGY AXIOMS

Terms describe entities from specific domains, e.g. for adrug ontology:

ParacetamolPatientA drug that contains 500 mg of paracetamol per tabletA patient who has age less than 6 years

Axioms formulate properties and restrictions using terms:

Panadol is a drug.Panadol contains paracetamol.Panadol contains 500 mg of paracetamol per tablet.[A patient who has age less than 6 years] should not beprescribed anything which [contains more than 250 mg ofparacetamol per tablet].

Restrictions specify ranges of data values:

500 mgmore than 250 mgless than 6 years

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 4/20

Page 17: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Introduction

ONTOLOGY AXIOMS

Terms describe entities from specific domains, e.g. for adrug ontology:

ParacetamolPatientA drug that contains 500 mg of paracetamol per tabletA patient who has age less than 6 years

Axioms formulate properties and restrictions using terms:

Panadol is a drug.Panadol contains paracetamol.Panadol contains 500 mg of paracetamol per tablet.[A patient who has age less than 6 years] should not beprescribed anything which [contains more than 250 mg ofparacetamol per tablet].

Restrictions specify ranges of data values:

500 mgmore than 250 mgless than 6 years

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 4/20

Page 18: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Introduction

ONTOLOGY AXIOMS

Terms describe entities from specific domains, e.g. for adrug ontology:

ParacetamolPatientA drug that contains 500 mg of paracetamol per tabletA patient who has age less than 6 years

Axioms formulate properties and restrictions using terms:Panadol is a drug.

Panadol contains paracetamol.Panadol contains 500 mg of paracetamol per tablet.[A patient who has age less than 6 years] should not beprescribed anything which [contains more than 250 mg ofparacetamol per tablet].

Restrictions specify ranges of data values:

500 mgmore than 250 mgless than 6 years

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 4/20

Page 19: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Introduction

ONTOLOGY AXIOMS

Terms describe entities from specific domains, e.g. for adrug ontology:

ParacetamolPatientA drug that contains 500 mg of paracetamol per tabletA patient who has age less than 6 years

Axioms formulate properties and restrictions using terms:Panadol is a drug.Panadol contains paracetamol.

Panadol contains 500 mg of paracetamol per tablet.[A patient who has age less than 6 years] should not beprescribed anything which [contains more than 250 mg ofparacetamol per tablet].

Restrictions specify ranges of data values:

500 mgmore than 250 mgless than 6 years

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 4/20

Page 20: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Introduction

ONTOLOGY AXIOMS

Terms describe entities from specific domains, e.g. for adrug ontology:

ParacetamolPatientA drug that contains 500 mg of paracetamol per tabletA patient who has age less than 6 years

Axioms formulate properties and restrictions using terms:Panadol is a drug.Panadol contains paracetamol.Panadol contains 500 mg of paracetamol per tablet.

[A patient who has age less than 6 years] should not beprescribed anything which [contains more than 250 mg ofparacetamol per tablet].

Restrictions specify ranges of data values:

500 mgmore than 250 mgless than 6 years

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 4/20

Page 21: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Introduction

ONTOLOGY AXIOMS

Terms describe entities from specific domains, e.g. for adrug ontology:

ParacetamolPatientA drug that contains 500 mg of paracetamol per tabletA patient who has age less than 6 years

Axioms formulate properties and restrictions using terms:Panadol is a drug.Panadol contains paracetamol.Panadol contains 500 mg of paracetamol per tablet.[A patient who has age less than 6 years] should not beprescribed anything which [contains more than 250 mg ofparacetamol per tablet].

Restrictions specify ranges of data values:

500 mgmore than 250 mgless than 6 years

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 4/20

Page 22: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Introduction

ONTOLOGY AXIOMS

Terms describe entities from specific domains, e.g. for adrug ontology:

ParacetamolPatientA drug that contains 500 mg of paracetamol per tabletA patient who has age less than 6 years

Axioms formulate properties and restrictions using terms:Panadol is a drug.Panadol contains paracetamol.Panadol contains 500 mg of paracetamol per tablet.[A patient who has age less than 6 years] should not beprescribed anything which [contains more than 250 mg ofparacetamol per tablet].

Restrictions specify ranges of data values:

500 mgmore than 250 mgless than 6 years

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 4/20

Page 23: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Introduction

ONTOLOGY AXIOMS

Terms describe entities from specific domains, e.g. for adrug ontology:

ParacetamolPatientA drug that contains 500 mg of paracetamol per tabletA patient who has age less than 6 years

Axioms formulate properties and restrictions using terms:Panadol is a drug.Panadol contains paracetamol.Panadol contains 500 mg of paracetamol per tablet.[A patient who has age less than 6 years] should not beprescribed anything which [contains more than 250 mg ofparacetamol per tablet].

Restrictions specify ranges of data values:500 mg

more than 250 mgless than 6 years

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 4/20

Page 24: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Introduction

ONTOLOGY AXIOMS

Terms describe entities from specific domains, e.g. for adrug ontology:

ParacetamolPatientA drug that contains 500 mg of paracetamol per tabletA patient who has age less than 6 years

Axioms formulate properties and restrictions using terms:Panadol is a drug.Panadol contains paracetamol.Panadol contains 500 mg of paracetamol per tablet.[A patient who has age less than 6 years] should not beprescribed anything which [contains more than 250 mg ofparacetamol per tablet].

Restrictions specify ranges of data values:500 mgmore than 250 mg

less than 6 years

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 4/20

Page 25: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Introduction

ONTOLOGY AXIOMS

Terms describe entities from specific domains, e.g. for adrug ontology:

ParacetamolPatientA drug that contains 500 mg of paracetamol per tabletA patient who has age less than 6 years

Axioms formulate properties and restrictions using terms:Panadol is a drug.Panadol contains paracetamol.Panadol contains 500 mg of paracetamol per tablet.[A patient who has age less than 6 years] should not beprescribed anything which [contains more than 250 mg ofparacetamol per tablet].

Restrictions specify ranges of data values:500 mgmore than 250 mgless than 6 years

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 4/20

Page 26: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Introduction

DESCRIPTION LOGICS

Formally describe axioms:

EXAMPLEPanadol v DrugPanadol v ∃contains.ParacetamolPanadol v ∃contains.(Paracetamol u ∃mgPerTablet.[= 500])Patient u ∃hasAge.[< 6] u ∃hasPrescription.

∃contains.(Paracetamol u ∃mgPerTablet.[> 250]) v ⊥

Atomic conceptsAtomic rolesDatatype restrictionsConcept constructorsFoundations of W3C ontology languages (OWL and OWL 2)

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 5/20

Page 27: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Introduction

DESCRIPTION LOGICS

Formally describe axioms:

EXAMPLEPanadol v DrugPanadol v ∃contains.ParacetamolPanadol v ∃contains.(Paracetamol u ∃mgPerTablet.[= 500])Patient u ∃hasAge.[< 6] u ∃hasPrescription.

∃contains.(Paracetamol u ∃mgPerTablet.[> 250]) v ⊥

Atomic concepts

Atomic rolesDatatype restrictionsConcept constructorsFoundations of W3C ontology languages (OWL and OWL 2)

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 5/20

Page 28: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Introduction

DESCRIPTION LOGICS

Formally describe axioms:

EXAMPLEPanadol v DrugPanadol v ∃contains.ParacetamolPanadol v ∃contains.(Paracetamol u ∃mgPerTablet.[= 500])Patient u ∃hasAge.[< 6] u ∃hasPrescription.

∃contains.(Paracetamol u ∃mgPerTablet.[> 250]) v ⊥

Atomic conceptsAtomic roles

Datatype restrictionsConcept constructorsFoundations of W3C ontology languages (OWL and OWL 2)

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 5/20

Page 29: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Introduction

DESCRIPTION LOGICS

Formally describe axioms:

EXAMPLEPanadol v DrugPanadol v ∃contains.ParacetamolPanadol v ∃contains.(Paracetamol u ∃mgPerTablet.[= 500])Patient u ∃hasAge.[< 6] u ∃hasPrescription.

∃contains.(Paracetamol u ∃mgPerTablet.[> 250]) v ⊥

Atomic conceptsAtomic rolesDatatype restrictions

Concept constructorsFoundations of W3C ontology languages (OWL and OWL 2)

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 5/20

Page 30: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Introduction

DESCRIPTION LOGICS

Formally describe axioms:

EXAMPLEPanadol v DrugPanadol v ∃contains.ParacetamolPanadol v ∃contains.(Paracetamol u ∃mgPerTablet.[= 500])Patient u ∃hasAge.[< 6] u ∃hasPrescription.

∃contains.(Paracetamol u ∃mgPerTablet.[> 250]) v ⊥

Atomic conceptsAtomic rolesDatatype restrictionsConcept constructors

Foundations of W3C ontology languages (OWL and OWL 2)

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 5/20

Page 31: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Introduction

DESCRIPTION LOGICS

Formally describe axioms:

EXAMPLEPanadol v DrugPanadol v ∃contains.ParacetamolPanadol v ∃contains.(Paracetamol u ∃mgPerTablet.[= 500])Patient u ∃hasAge.[< 6] u ∃hasPrescription.

∃contains.(Paracetamol u ∃mgPerTablet.[> 250]) v ⊥

Atomic conceptsAtomic rolesDatatype restrictionsConcept constructorsFoundations of W3C ontology languages (OWL and OWL 2)

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 5/20

Page 32: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Introduction

DESCRIPTION LOGICS REASONING

EXAMPLEPanadol v ∃contains.(Paracetamol u ∃mgPerTablet.[= 500])

Patient u ∃hasAge.[< 6] u ∃hasPrescription.∃contains.(Paracetamol u ∃mgPerTablet.[> 250]) v ⊥

Can Panadol be prescribed to a 3-year-old patient?- Is X satisfiable?DL reasoning tasks:

Check satisfiability of a concept (O |= X v ⊥)Check satisfiability of an ontology (O |= ⊥ )Check subsumption (O |= A v B)Classification (compute all A v B such that O |= A v B) more general than all tasks above

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 6/20

Page 33: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Introduction

DESCRIPTION LOGICS REASONING

EXAMPLEPanadol v ∃contains.(Paracetamol u ∃mgPerTablet.[= 500])

Patient u ∃hasAge.[< 6] u ∃hasPrescription.∃contains.(Paracetamol u ∃mgPerTablet.[> 250]) v ⊥

Can Panadol be prescribed to a 3-year-old patient?

- Is X satisfiable?DL reasoning tasks:

Check satisfiability of a concept (O |= X v ⊥)Check satisfiability of an ontology (O |= ⊥ )Check subsumption (O |= A v B)Classification (compute all A v B such that O |= A v B) more general than all tasks above

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 6/20

Page 34: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Introduction

DESCRIPTION LOGICS REASONING

EXAMPLEPanadol v ∃contains.(Paracetamol u ∃mgPerTablet.[= 500])

Patient u ∃hasAge.[< 6] u ∃hasPrescription.∃contains.(Paracetamol u ∃mgPerTablet.[> 250]) v ⊥

X ≡ Patient u ∃hasAge.[= 3] u ∃hasPrescription.Panadol

Can Panadol be prescribed to a 3-year-old patient?- Is X satisfiable?

DL reasoning tasks:Check satisfiability of a concept (O |= X v ⊥)Check satisfiability of an ontology (O |= ⊥ )Check subsumption (O |= A v B)Classification (compute all A v B such that O |= A v B) more general than all tasks above

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 6/20

Page 35: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Introduction

DESCRIPTION LOGICS REASONING

EXAMPLEPanadol v ∃contains.(Paracetamol u ∃mgPerTablet.[= 500])

Patient u ∃hasAge.[< 6] u ∃hasPrescription.∃contains.(Paracetamol u ∃mgPerTablet.[> 250]) v ⊥

X ≡ Patient u ∃hasAge.[= 3] u ∃hasPrescription.Panadol

Can Panadol be prescribed to a 3-year-old patient?- Is X satisfiable?DL reasoning tasks:

Check satisfiability of a concept (O |= X v ⊥)Check satisfiability of an ontology (O |= ⊥ )Check subsumption (O |= A v B)Classification (compute all A v B such that O |= A v B) more general than all tasks above

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 6/20

Page 36: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Introduction

EL AND DATATYPES

EL [Baader et al., IJCAI 2005] is a simple DL:

uses u and ∃:Panadol ≡ Drug u ∃contains.Paracetamol

suitable for large-scale ontologies such as SNOMED or GOreasoning in PTIME

EL with datatypes is EXPTIME-complete. Why?EL extended with disjunction is EXPTIME-complete anddisjunction is expressible using datatypes:

Baader et al. [IJCAI 2005] ensure polynomiality byrestrictions on datatype useEL Profile of OWL 2 admits only equalityAbsence of inequalities reduces the utility of OWL 2 EL

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 7/20

Page 37: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Introduction

EL AND DATATYPES

EL [Baader et al., IJCAI 2005] is a simple DL:

uses u and ∃:Panadol ≡ Drug u ∃contains.Paracetamol

suitable for large-scale ontologies such as SNOMED or GOreasoning in PTIME

EL with datatypes is EXPTIME-complete. Why?

EL extended with disjunction is EXPTIME-complete anddisjunction is expressible using datatypes:

Baader et al. [IJCAI 2005] ensure polynomiality byrestrictions on datatype useEL Profile of OWL 2 admits only equalityAbsence of inequalities reduces the utility of OWL 2 EL

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 7/20

Page 38: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Introduction

EL AND DATATYPES

EL [Baader et al., IJCAI 2005] is a simple DL:

uses u and ∃:Panadol ≡ Drug u ∃contains.Paracetamol

suitable for large-scale ontologies such as SNOMED or GOreasoning in PTIME

EL with datatypes is EXPTIME-complete. Why?EL extended with disjunction is EXPTIME-complete anddisjunction is expressible using datatypes:

Baader et al. [IJCAI 2005] ensure polynomiality byrestrictions on datatype useEL Profile of OWL 2 admits only equalityAbsence of inequalities reduces the utility of OWL 2 EL

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 7/20

Page 39: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Introduction

EL AND DATATYPES

EL [Baader et al., IJCAI 2005] is a simple DL:

uses u and ∃:Panadol ≡ Drug u ∃contains.Paracetamol

suitable for large-scale ontologies such as SNOMED or GOreasoning in PTIME

EL with datatypes is EXPTIME-complete. Why?EL extended with disjunction is EXPTIME-complete anddisjunction is expressible using datatypes:

<,=

Baader et al. [IJCAI 2005] ensure polynomiality byrestrictions on datatype useEL Profile of OWL 2 admits only equalityAbsence of inequalities reduces the utility of OWL 2 EL

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 7/20

Page 40: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Introduction

EL AND DATATYPES

EL [Baader et al., IJCAI 2005] is a simple DL:uses u and ∃:

Panadol ≡ Drug u ∃contains.Paracetamolsuitable for large-scale ontologies such as SNOMED or GOreasoning in PTIME

EL with datatypes is EXPTIME-complete. Why?EL extended with disjunction is EXPTIME-complete anddisjunction is expressible using datatypes:

<,=

EXAMPLE

A v ∃F.[< 2]∃F.[= 1] v B∃F.[= 0] v C

A v B t C

Baader et al. [IJCAI 2005] ensure polynomiality byrestrictions on datatype useEL Profile of OWL 2 admits only equalityAbsence of inequalities reduces the utility of OWL 2 EL

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 7/20

Page 41: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Introduction

EL AND DATATYPES

EL [Baader et al., IJCAI 2005] is a simple DL:

uses u and ∃:Panadol ≡ Drug u ∃contains.Paracetamol

suitable for large-scale ontologies such as SNOMED or GOreasoning in PTIME

EL with datatypes is EXPTIME-complete. Why?EL extended with disjunction is EXPTIME-complete anddisjunction is expressible using datatypes:

<,= >,= <,> ≤,= ≥,= ≤,≥

Baader et al. [IJCAI 2005] ensure polynomiality byrestrictions on datatype useEL Profile of OWL 2 admits only equalityAbsence of inequalities reduces the utility of OWL 2 EL

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 7/20

Page 42: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Introduction

EL AND DATATYPES

EL [Baader et al., IJCAI 2005] is a simple DL:

uses u and ∃:Panadol ≡ Drug u ∃contains.Paracetamol

suitable for large-scale ontologies such as SNOMED or GOreasoning in PTIME

EL with datatypes is EXPTIME-complete. Why?EL extended with disjunction is EXPTIME-complete anddisjunction is expressible using datatypes:

<,= >,= <,> ≤,= ≥,= ≤,≥Baader et al. [IJCAI 2005] ensure polynomiality byrestrictions on datatype use

EL Profile of OWL 2 admits only equalityAbsence of inequalities reduces the utility of OWL 2 EL

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 7/20

Page 43: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Introduction

EL AND DATATYPES

EL [Baader et al., IJCAI 2005] is a simple DL:

uses u and ∃:Panadol ≡ Drug u ∃contains.Paracetamol

suitable for large-scale ontologies such as SNOMED or GOreasoning in PTIME

EL with datatypes is EXPTIME-complete. Why?EL extended with disjunction is EXPTIME-complete anddisjunction is expressible using datatypes:

<,= >,= <,> ≤,= ≥,= ≤,≥Baader et al. [IJCAI 2005] ensure polynomiality byrestrictions on datatype use

EL Profile of OWL 2 admits only equalityAbsence of inequalities reduces the utility of OWL 2 EL

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 7/20

Page 44: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Introduction

EL AND DATATYPES

EL [Baader et al., IJCAI 2005] is a simple DL:

uses u and ∃:Panadol ≡ Drug u ∃contains.Paracetamol

suitable for large-scale ontologies such as SNOMED or GOreasoning in PTIME

EL with datatypes is EXPTIME-complete. Why?EL extended with disjunction is EXPTIME-complete anddisjunction is expressible using datatypes:

<,= >,= <,> ≤,= ≥,= ≤,≥Baader et al. [IJCAI 2005] ensure polynomiality byrestrictions on datatype useEL Profile of OWL 2 admits only equality

Absence of inequalities reduces the utility of OWL 2 EL

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 7/20

Page 45: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Introduction

EL AND DATATYPES

EL [Baader et al., IJCAI 2005] is a simple DL:

uses u and ∃:Panadol ≡ Drug u ∃contains.Paracetamol

suitable for large-scale ontologies such as SNOMED or GOreasoning in PTIME

EL with datatypes is EXPTIME-complete. Why?EL extended with disjunction is EXPTIME-complete anddisjunction is expressible using datatypes:

<,= >,= <,> ≤,= ≥,= ≤,≥Baader et al. [IJCAI 2005] ensure polynomiality byrestrictions on datatype useEL Profile of OWL 2 admits only equalityAbsence of inequalities reduces the utility of OWL 2 EL

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 7/20

Page 46: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Introduction

RESULTS OVERVIEW

Relax the restrictions on datatype use by allowinginequalities and remaining polynomial

Key ideaDistinguish negative (LHS of axiom) and positive (RHS ofaxiom) occurrences of datatypes

Main results

Full classification of cases where datatypes are used andtractability is preserved for N, Z, Q and R

Polynomial, sound and complete reasoning procedure forextensions of EL⊥ with restricted numerical datatypes

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 8/20

Page 47: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Introduction

RESULTS OVERVIEW

Relax the restrictions on datatype use by allowinginequalities and remaining polynomial

Key ideaDistinguish negative (LHS of axiom) and positive (RHS ofaxiom) occurrences of datatypes

Main results

Full classification of cases where datatypes are used andtractability is preserved for N, Z, Q and R

Polynomial, sound and complete reasoning procedure forextensions of EL⊥ with restricted numerical datatypes

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 8/20

Page 48: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Introduction

RESULTS OVERVIEW

Relax the restrictions on datatype use by allowinginequalities and remaining polynomial

Key ideaDistinguish negative (LHS of axiom) and positive (RHS ofaxiom) occurrences of datatypes

Main results

Full classification of cases where datatypes are used andtractability is preserved for N, Z, Q and R

Polynomial, sound and complete reasoning procedure forextensions of EL⊥ with restricted numerical datatypes

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 8/20

Page 49: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Introduction

RESULTS OVERVIEW

Relax the restrictions on datatype use by allowinginequalities and remaining polynomial

Key ideaDistinguish negative (LHS of axiom) and positive (RHS ofaxiom) occurrences of datatypes

Main results

Full classification of cases where datatypes are used andtractability is preserved for N, Z, Q and R

Polynomial, sound and complete reasoning procedure forextensions of EL⊥ with restricted numerical datatypes

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 8/20

Page 50: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Introduction

EL FAMILY OF DESCRIPTION LOGICS

The EL language:

Syntax SemanticsAtomic concept C C(x)Top > >Conjunction C u D C(x) ∧ D(x)Existential restriction ∃R.C ∃y : R(x, y) ∧ C(y)

EL⊥ with Numerical Datatypes

Bottom ⊥ ⊥Datatype restriction ∃F.range ∃v : F(x, v) ∧ v ∈ range

range = [< n] | [≤ n] | [> n] | [≥ n] | [= n] ⊆ D = N,Z,R,QAxioms

Concept inclusion C v D ∀x : C(x)→ D(x)

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 9/20

Page 51: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Introduction

EL FAMILY OF DESCRIPTION LOGICS

The EL language:

Syntax SemanticsAtomic concept C C(x)Top > >Conjunction C u D C(x) ∧ D(x)Existential restriction ∃R.C ∃y : R(x, y) ∧ C(y)

EL⊥ with Numerical Datatypes

Bottom ⊥ ⊥Datatype restriction ∃F.range ∃v : F(x, v) ∧ v ∈ range

range = [< n] | [≤ n] | [> n] | [≥ n] | [= n] ⊆ D = N,Z,R,Q

Axioms

Concept inclusion C v D ∀x : C(x)→ D(x)

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 9/20

Page 52: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Introduction

EL FAMILY OF DESCRIPTION LOGICS

The EL language:

Syntax SemanticsAtomic concept C C(x)Top > >Conjunction C u D C(x) ∧ D(x)Existential restriction ∃R.C ∃y : R(x, y) ∧ C(y)

EL⊥ with Numerical Datatypes

Bottom ⊥ ⊥Datatype restriction ∃F.range ∃v : F(x, v) ∧ v ∈ range

range = [< n] | [≤ n] | [> n] | [≥ n] | [= n] ⊆ D = N,Z,R,QAxioms

Concept inclusion C v D ∀x : C(x)→ D(x)

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 9/20

Page 53: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Introduction

EL FAMILY OF DESCRIPTION LOGICS

The EL language:

Syntax SemanticsAtomic concept C C(x)Top > >Conjunction C u D C(x) ∧ D(x)Existential restriction ∃R.C ∃y : R(x, y) ∧ C(y)

EL⊥ with Numerical Datatypes

Bottom ⊥ ⊥Datatype restriction ∃F.range ∃v : F(x, v) ∧ v ∈ range

range = [< n] | [≤ n] | [> n] | [≥ n] | [= n] ⊆ D = N,Z,R,QAxioms

Concept inclusion C v D ∀x : C(x)→ D(x)

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 9/20

Page 54: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Reasoning in EL⊥(D)

OUTLINE

1 INTRODUCTION

2 REASONING IN EL⊥(D)

3 CONCLUSION

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 10/20

Page 55: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Reasoning in EL⊥(D)

ALGORITHM STAGES

1 Standard normalization of the axioms

Normal formsNF1 A v BNF2 A1 u A2 v BNF3 A v ∃R.BNF4 ∃R.B v ANF5 A v ∃F.rangeNF6 ∃F.range v A

2 Saturation of the axioms under inference rules, such as:

A v B A v CA v D

B u C v D ∈ O

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 11/20

Page 56: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Reasoning in EL⊥(D)

ALGORITHM STAGES

1 Standard normalization of the axioms

Normal formsNF1 A v BNF2 A1 u A2 v BNF3 A v ∃R.BNF4 ∃R.B v ANF5 A v ∃F.rangeNF6 ∃F.range v A

2 Saturation of the axioms under inference rules, such as:

A v B A v CA v D

B u C v D ∈ O

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 11/20

Page 57: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Reasoning in EL⊥(D)

REASONING RULES (PART I)

Rules from EL⊥

IR1A v A

IR2A v > CR1

A v BA v C

B v C ∈ O

CR2A v B A v C

A v DB u C v D ∈ O

CR3A v B

A v ∃R.CB v ∃R.C ∈ O

CR4A v ∃R.B B v C

A v D∃R.C v D ∈ O

CR5A v ∃R.B B v ⊥

A v ⊥

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 12/20

Page 58: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Reasoning in EL⊥(D)

REASONING RULES (PART II)

New rules for datatypes

A v ∃F.[< m]

A v B∃F.[< n] v B ∈ O, m ≤ n

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 13/20

Page 59: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Reasoning in EL⊥(D)

REASONING RULES (PART II)

New rules for datatypes

ID1A v ⊥

A v ∃F.[< 0] ∈ O

CD1A v B

A v ∃F.rangeB v ∃F.range ∈ O

CD2(<,<)A v ∃F.[< m]

A v B∃F.[< n] v B ∈ O, m ≤ n

CD2(=,<)A v ∃F.[= m]

A v B∃F.[< n] v B ∈ O, m < n

CD2(=,=)A v ∃F.[= m]

A v B∃F.[= n] v B ∈ O, m = n . . .

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 13/20

Page 60: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Reasoning in EL⊥(D)

THE EL⊥(D)ALGORITHM

The algorithm is:

sound: all rules derive logical consequences of premises

polynomial as only polynomially many axioms are possible

not complete in general (EL⊥(D) is EXPTIME-complete)

complete under certain restrictions on datatypes

What type of restrictions?

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 14/20

Page 61: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Reasoning in EL⊥(D)

THE EL⊥(D)ALGORITHM

The algorithm is:

sound: all rules derive logical consequences of premises

polynomial as only polynomially many axioms are possible

not complete in general (EL⊥(D) is EXPTIME-complete)

complete under certain restrictions on datatypes

What type of restrictions?

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 14/20

Page 62: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Reasoning in EL⊥(D)

THE EL⊥(D)ALGORITHM

The algorithm is:

sound: all rules derive logical consequences of premises

polynomial as only polynomially many axioms are possible

not complete in general (EL⊥(D) is EXPTIME-complete)

complete under certain restrictions on datatypes

What type of restrictions?

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 14/20

Page 63: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Reasoning in EL⊥(D)

THE EL⊥(D)ALGORITHM

The algorithm is:

sound: all rules derive logical consequences of premises

polynomial as only polynomially many axioms are possible

not complete in general (EL⊥(D) is EXPTIME-complete)

complete under certain restrictions on datatypes

What type of restrictions?

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 14/20

Page 64: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Reasoning in EL⊥(D)

THE EL⊥(D)ALGORITHM

The algorithm is:

sound: all rules derive logical consequences of premises

polynomial as only polynomially many axioms are possible

not complete in general (EL⊥(D) is EXPTIME-complete)

complete under certain restrictions on datatypes

What type of restrictions?

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 14/20

Page 65: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Reasoning in EL⊥(D)

RESTRICTIONS FOR N

Negative relations Positive relations<,≤, >,≥,= =

EXAMPLEPanadol v ∃contains.(Paracetamol u ∃mgPerTablet.[= 500])

Patient u ∃hasAge.[< 6] u ∃hasPrescription.∃contains.(Paracetamol u ∃mgPerTablet.[> 250]) v ⊥

X v Patient u ∃hasAge.[= 3] u ∃hasPrescription.Panadol

Restrict positive and negative occurrences of datatyperelations so as disjunction is not expressible

All restrictions are maximal:

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 15/20

Page 66: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Reasoning in EL⊥(D)

RESTRICTIONS FOR N

Negative relations Positive relations<,≤, >,≥,= =

EXAMPLEPanadol v ∃contains.(Paracetamol u ∃mgPerTablet.[= 500])

Patient u ∃hasAge.[< 6] u ∃hasPrescription.∃contains.(Paracetamol u ∃mgPerTablet.[> 250]) v ⊥

X v Patient u ∃hasAge.[= 3] u ∃hasPrescription.Panadol

Restrict positive and negative occurrences of datatyperelations so as disjunction is not expressible

All restrictions are maximal:

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 15/20

Page 67: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Reasoning in EL⊥(D)

RESTRICTIONS FOR N

Negative relations Positive relations<,≤, >,≥,= =

EXAMPLEPanadol v ∃contains.(Paracetamol u ∃mgPerTablet.[= 500])

Patient u ∃hasAge.[< 6] u ∃hasPrescription.∃contains.(Paracetamol u ∃mgPerTablet.[> 250]) v ⊥

X v Patient u ∃hasAge.[= 3] u ∃hasPrescription.Panadol

Restrict positive and negative occurrences of datatyperelations so as disjunction is not expressible

All restrictions are maximal:

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 15/20

Page 68: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Reasoning in EL⊥(D)

RESTRICTIONS FOR N

Negative relations Positive relations<,≤, >,≥,= =

<,≤ <,≤, >,≥,=>,≥ <,≤, >,≥,=

<,≤,= >,≥,=

All restrictions are maximal:

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 15/20

Page 69: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Reasoning in EL⊥(D)

RESTRICTIONS FOR N

Negative relations Positive relations<,≤, >,≥,= =

<,≤ <,≤, >,≥,=>,≥ <,≤, >,≥,=

<,≤,= >,≥,=

All restrictions are maximal:

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 15/20

Page 70: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Reasoning in EL⊥(D)

RESTRICTIONS FOR N

Negative relations Positive relations<,≤, >,≥,= = ,<

<,≤ <,≤, >,≥,=>,≥ <,≤, >,≥,=

<,≤,= >,≥,=

All restrictions are maximal:

EXAMPLE

A v ∃F.[< 2]∃F.[= 1] v B∃F.[= 0] v C

A v B t C

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 15/20

Page 71: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Reasoning in EL⊥(D)

RESTRICTIONS FOR ZNegative relations Positive relations

<,≤, >,≥,= == <,≤, >,≥,=

<,≤ <,≤, >,≥,=>,≥ <,≤, >,≥,=

<,≤,= >,≥,=>,≥,= <,≤,=

Additional datatype restrictions: integers do not have aminimal element such as 0.

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 16/20

Page 72: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Reasoning in EL⊥(D)

RESTRICTIONS FOR ZNegative relations Positive relations

<,≤, >,≥,= == <,≤, >,≥,=

<,≤ <,≤, >,≥,=>,≥ <,≤, >,≥,=

<,≤,= >,≥,=>,≥,= <,≤,=

Additional datatype restrictions: integers do not have aminimal element such as 0.

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 16/20

Page 73: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Reasoning in EL⊥(D)

RESTRICTIONS FOR ZNegative relations Positive relations

<,≤, >,≥,= == <,≤, >,≥,=

<,≤ <,≤, >,≥,=>,≥ <,≤, >,≥,=

<,≤,= >,≥,=>,≥,= <,≤,=

Additional datatype restrictions: integers do not have aminimal element such as 0.

EXAMPLE

A v ∃F.[< 2]∃F.[= 1] v B∃F.[= 0] v C

A 6v B t C

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 16/20

Page 74: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Reasoning in EL⊥(D)

RESTRICTIONS FOR Q AND RNegative relations Positive relations

<,≤, >,≥,= =≤,= <,≤, >,≥,=≥,= <,≤, >,≥,=<,≤ <,≤, >,≥,=>,≥ <,≤, >,≥,=

<,≤,= <,>,≥,=>,≥,= <,≤, >,=

Between every two different numbers there exists a thirdone:

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 17/20

Page 75: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Reasoning in EL⊥(D)

RESTRICTIONS FOR Q AND RNegative relations Positive relations

<,≤, >,≥,= =≤,= <,≤, >,≥,=≥,= <,≤, >,≥,=<,≤ <,≤, >,≥,=>,≥ <,≤, >,≥,=

<,≤,= <,>,≥,=>,≥,= <,≤, >,=

Between every two different numbers there exists a thirdone:

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 17/20

Page 76: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Reasoning in EL⊥(D)

RESTRICTIONS FOR Q AND RNegative relations Positive relations

<,≤, >,≥,= =≤,= <,≤, >,≥,=≥,= <,≤, >,≥,=<,≤ <,≤, >,≥,=>,≥ <,≤, >,≥,=

<,≤,= <,>,≥,=>,≥,= <,≤, >,=

Between every two different numbers there exists a thirdone:

EXAMPLE

A v ∃F.[< 3]∃F.[= 2] v B∃F.[< 2] v C

A 6v B t C

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 17/20

Page 77: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Conclusion

OUTLINE

1 INTRODUCTION

2 REASONING IN EL⊥(D)

3 CONCLUSION

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 18/20

Page 78: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Conclusion

RESULTS OVERVIEWPolynomial, sound and complete reasoning procedure forextensions of EL⊥ with “safe” numerical datatypesFull classification of tractable cases for N, Z, Q and RCommon restriction for N, Z, Q and R:

EXAMPLEPanadol v ∃contains.(Paracetamol u ∃mgPerTablet.[= 500])

Patient u ∃hasAge.[< 6] u ∃hasPrescription.∃contains.(Paracetamol u ∃mgPerTablet.[> 250]) v ⊥

X v Patient u ∃hasAge.[= 3] u ∃hasPrescription.Panadol

Candidate for an OWL 2 EL Profile extension

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 19/20

Page 79: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Conclusion

RESULTS OVERVIEWPolynomial, sound and complete reasoning procedure forextensions of EL⊥ with “safe” numerical datatypesFull classification of tractable cases for N, Z, Q and RCommon restriction for N, Z, Q and R:

Negative relations Positive relations<,≤, >,≥,= =

EXAMPLEPanadol v ∃contains.(Paracetamol u ∃mgPerTablet.[= 500])

Patient u ∃hasAge.[< 6] u ∃hasPrescription.∃contains.(Paracetamol u ∃mgPerTablet.[> 250]) v ⊥

X v Patient u ∃hasAge.[= 3] u ∃hasPrescription.Panadol

Candidate for an OWL 2 EL Profile extension

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 19/20

Page 80: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Conclusion

RESULTS OVERVIEWPolynomial, sound and complete reasoning procedure forextensions of EL⊥ with “safe” numerical datatypesFull classification of tractable cases for N, Z, Q and RCommon restriction for N, Z, Q and R:

Negative relations Positive relations<,≤, >,≥,= =

EXAMPLEPanadol v ∃contains.(Paracetamol u ∃mgPerTablet.[= 500])

Patient u ∃hasAge.[< 6] u ∃hasPrescription.∃contains.(Paracetamol u ∃mgPerTablet.[> 250]) v ⊥

X v Patient u ∃hasAge.[= 3] u ∃hasPrescription.Panadol

Candidate for an OWL 2 EL Profile extension

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 19/20

Page 81: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Conclusion

RESULTS OVERVIEWPolynomial, sound and complete reasoning procedure forextensions of EL⊥ with “safe” numerical datatypesFull classification of tractable cases for N, Z, Q and RCommon restriction for N, Z, Q and R:

Negative relations Positive relations<,≤, >,≥,= =

EXAMPLEPanadol v ∃contains.(Paracetamol u ∃mgPerTablet.[= 500])

Patient u ∃hasAge.[< 6] u ∃hasPrescription.∃contains.(Paracetamol u ∃mgPerTablet.[> 250]) v ⊥

X v Patient u ∃hasAge.[= 3] u ∃hasPrescription.Panadol

Candidate for an OWL 2 EL Profile extension

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 19/20

Page 82: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Conclusion

RESULTS OVERVIEWPolynomial, sound and complete reasoning procedure forextensions of EL⊥ with “safe” numerical datatypesFull classification of tractable cases for N, Z, Q and RCommon restriction for N, Z, Q and R:

Negative relations Positive relations<,≤, >,≥,= =

EXAMPLEPanadol v ∃contains.(Paracetamol u ∃mgPerTablet.[= 500])

Patient u ∃hasAge.[< 6] u ∃hasPrescription.∃contains.(Paracetamol u ∃mgPerTablet.[> 250]) v ⊥

X v Patient u ∃hasAge.[= 3] u ∃hasPrescription.Panadol

Candidate for an OWL 2 EL Profile extension

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 19/20

Page 83: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Conclusion

RESULTS OVERVIEWPolynomial, sound and complete reasoning procedure forextensions of EL⊥ with “safe” numerical datatypesFull classification of tractable cases for N, Z, Q and RCommon restriction for N, Z, Q and R:

Negative relations Positive relations<,≤, >,≥,= =

EXAMPLEPanadol v ∃contains.(Paracetamol u ∃mgPerTablet.[= 500])

Patient u ∃hasAge.[< 6] u ∃hasPrescription.∃contains.(Paracetamol u ∃mgPerTablet.[> 250]) v ⊥

X v Patient u ∃hasAge.[= 3] u ∃hasPrescription.Panadol

Candidate for an OWL 2 EL Profile extension

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 19/20

Page 84: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Conclusion

FUTURE WORK

Extend the reasoning algorithm:

complex role inclusionsfunctional data propertiesnominalsdomain and range restrictionsHorn SHIQ [Kazakov, IJCAI, 2009]

More fine-grained analysis by also considering which dataproperties are used with relations

Thank you for your attention! Questions?

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 20/20

Page 85: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Conclusion

FUTURE WORK

Extend the reasoning algorithm:complex role inclusionsfunctional data propertiesnominalsdomain and range restrictionsHorn SHIQ [Kazakov, IJCAI, 2009]

More fine-grained analysis by also considering which dataproperties are used with relations

Thank you for your attention! Questions?

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 20/20

Page 86: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Conclusion

FUTURE WORK

Extend the reasoning algorithm:complex role inclusionsfunctional data propertiesnominalsdomain and range restrictionsHorn SHIQ [Kazakov, IJCAI, 2009]

More fine-grained analysis by also considering which dataproperties are used with relations

Thank you for your attention! Questions?

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 20/20

Page 87: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Conclusion

FUTURE WORK

Extend the reasoning algorithm:complex role inclusionsfunctional data propertiesnominalsdomain and range restrictionsHorn SHIQ [Kazakov, IJCAI, 2009]

More fine-grained analysis by also considering which dataproperties are used with relations

Thank you for your attention! Questions?

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 20/20

Page 88: Tractable Extensions of the Description Logic EL with Numerical Datatypes

Conclusion

FUTURE WORK

Extend the reasoning algorithm:complex role inclusionsfunctional data propertiesnominalsdomain and range restrictionsHorn SHIQ [Kazakov, IJCAI, 2009]

More fine-grained analysis by also considering which dataproperties are used with relations

Thank you for your attention! Questions?

Despoina Magka, Yevgeny Kazakov and Ian Horrocks Tractable Extensions of EL with Numerical Datatypes 20/20