Query-Based Entailment and Inseparability for ALC Ontologies Elena - - PowerPoint PPT Presentation

query based entailment and inseparability for alc
SMART_READER_LITE
LIVE PREVIEW

Query-Based Entailment and Inseparability for ALC Ontologies Elena - - PowerPoint PPT Presentation

Query-Based Entailment and Inseparability for ALC Ontologies Elena Botoeva Faculty of Computer Science, Free University of Bozen-Bolzano, Italy joint work with Carsten Lutz, Vladislav Ryzhikov, Frank Wolter and Michael Zakharyaschev Elena


slide-1
SLIDE 1

Query-Based Entailment and Inseparability for ALC Ontologies

Elena Botoeva

Faculty of Computer Science, Free University of Bozen-Bolzano, Italy

joint work with Carsten Lutz, Vladislav Ryzhikov, Frank Wolter and Michael Zakharyaschev

Elena Botoeva(FUB) Query-Based Entailment and Inseparability for ALC Ontologies 1/7

slide-2
SLIDE 2

Query Inseparability for Ontologies

By an ontology O we mean

  • a knowledge base K = (T , A), or
  • a TBox T .

Query answering over ontologies is an important reasoning task.

Elena Botoeva(FUB) Query-Based Entailment and Inseparability for ALC Ontologies 2/7

slide-3
SLIDE 3

Query Inseparability for Ontologies

By an ontology O we mean

  • a knowledge base K = (T , A), or
  • a TBox T .

Query answering over ontologies is an important reasoning task. Ontologies O1 and O2 are query-inseparable when we cannot distinguish between them by means of queries.

Elena Botoeva(FUB) Query-Based Entailment and Inseparability for ALC Ontologies 2/7

slide-4
SLIDE 4

Query Inseparability for Ontologies

By an ontology O we mean

  • a knowledge base K = (T , A), or
  • a TBox T .

Query answering over ontologies is an important reasoning task. Ontologies O1 and O2 are query-inseparable when we cannot distinguish between them by means of queries.

Applications

  • extracting modules
  • comparing versions of an ontology
  • forgetting some symbols from an ontology
  • exchanging knowledge

Elena Botoeva(FUB) Query-Based Entailment and Inseparability for ALC Ontologies 2/7

slide-5
SLIDE 5

Query Inseparability for Knowledge Bases

Consider a class of queries Q ∈ {CQ, UCQ}, and a signature Σ of concept and role names. KBs K1 = (T1, A1) and K2 = (T2, A2) are Σ-Q inseparable, K1 ≡Q

Σ K2, if

K1 | = q(a) ⇐ ⇒ K2 | = q(a) for all Σ-queries q ∈ Q and all individuals a in K1 and K2.

Elena Botoeva(FUB) Query-Based Entailment and Inseparability for ALC Ontologies 3/7

slide-6
SLIDE 6

Query Inseparability for Knowledge Bases

Consider a class of queries Q ∈ {CQ, UCQ}, and a signature Σ of concept and role names. KBs K1 = (T1, A1) and K2 = (T2, A2) are Σ-Q inseparable, K1 ≡Q

Σ K2, if

K1 | = q(a) ⇐ ⇒ K2 | = q(a) for all Σ-queries q ∈ Q and all individuals a in K1 and K2. Σ = { spots }

Elena Botoeva(FUB) Query-Based Entailment and Inseparability for ALC Ontologies 3/7

slide-7
SLIDE 7

Examples

Query inseparability is different from logical equivalence: K1 = ( {A ⊑ B}, {A(a)} ) and K2 = ( ∅, {A(a), B(a)} ) K1 ≡ K2 but K1 ≡(U)CQ

{A,B} K2

Elena Botoeva(FUB) Query-Based Entailment and Inseparability for ALC Ontologies 4/7

slide-8
SLIDE 8

Examples

Query inseparability is different from logical equivalence: K1 = ( {A ⊑ B}, {A(a)} ) and K2 = ( ∅, {A(a), B(a)} ) K1 ≡ K2 but K1 ≡(U)CQ

{A,B} K2

Elena Botoeva(FUB) Query-Based Entailment and Inseparability for ALC Ontologies 4/7

slide-9
SLIDE 9

Examples

Query inseparability is different from logical equivalence: K1 = ( {A ⊑ B}, {A(a)} ) and K2 = ( ∅, {A(a), B(a)} ) K1 ≡ K2 but K1 ≡(U)CQ

{A,B} K2

UCQ-inseparability and CQ-inseparability are distinct: K1 = ( {A ⊑ B ⊔ C}, {A(a)} ) and K2 = ( ∅, {A(a)} )

Elena Botoeva(FUB) Query-Based Entailment and Inseparability for ALC Ontologies 4/7

slide-10
SLIDE 10

Examples

Query inseparability is different from logical equivalence: K1 = ( {A ⊑ B}, {A(a)} ) and K2 = ( ∅, {A(a), B(a)} ) K1 ≡ K2 but K1 ≡(U)CQ

{A,B} K2

UCQ-inseparability and CQ-inseparability are distinct: K1 = ( {A ⊑ B ⊔ C}, {A(a)} ) and K2 = ( ∅, {A(a)} ) K1 ≡UCQ

{A,B,C} K2

but K1 ≡CQ

{A,B,C} K2

Elena Botoeva(FUB) Query-Based Entailment and Inseparability for ALC Ontologies 4/7

slide-11
SLIDE 11

Examples

Query inseparability is different from logical equivalence: K1 = ( {A ⊑ B}, {A(a)} ) and K2 = ( ∅, {A(a), B(a)} ) K1 ≡ K2 but K1 ≡(U)CQ

{A,B} K2

UCQ-inseparability and CQ-inseparability are distinct: K1 = ( {A ⊑ B ⊔ C}, {A(a)} ) and K2 = ( ∅, {A(a)} ) K1 ≡UCQ

{A,B,C} K2

but K1 ≡CQ

{A,B,C} K2

Signature makes a difference: K1 ≡UCQ

{A} K2

Elena Botoeva(FUB) Query-Based Entailment and Inseparability for ALC Ontologies 4/7

slide-12
SLIDE 12

Query Inseparability for TBoxes

Consider signatures: Σ1 for ABoxes and Σ2 for queries. TBoxes T1 and T2 are (Σ1, Σ2)-(U)CQ inseparable, T1 ≡(U)CQ

(Σ1,Σ2) T2, if

(T1, A) ≡(U)CQ

Σ2

(T2, A) for all Σ1-ABoxes A.

Elena Botoeva(FUB) Query-Based Entailment and Inseparability for ALC Ontologies 5/7

slide-13
SLIDE 13

Main Results

KBs:

  • (rooted) CQ-inseparability undecidable for ALC.
  • (rooted) UCQ-inseparability 2ExpTime-complete.

TBoxes:

  • (rooted) CQ-inseparability undecidable for ALC.
  • CQ/UCQ-inseparability 2ExpTime-complete for Horn-ALC.
  • rooted CQ/UCQ-inseparability ExpTime-complete for Horn-ALC.

Elena Botoeva(FUB) Query-Based Entailment and Inseparability for ALC Ontologies 6/7

slide-14
SLIDE 14

See you at the poster!

Elena Botoeva(FUB) Query-Based Entailment and Inseparability for ALC Ontologies 7/7