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09/18/2023
Towards Ontology Construction with Language Models
We present a method for automatically constructing a concept hierarchy f...
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06/07/2023
Querying Circumscribed Description Logic Knowledge Bases
Circumscription is one of the main approaches for defining non-monotonic...
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06/06/2023
Description Logics with Abstraction and Refinement
Ontologies often require knowledge representation on multiple levels of ...
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05/15/2023
SAT-Based PAC Learning of Description Logic Concepts
We propose bounded fitting as a scheme for learning description logic co...
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11/28/2022
Efficient Answer Enumeration in Description Logics with Functional Roles – Extended Version
We study the enumeration of answers to ontology-mediated queries when th...
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08/22/2022
On the non-efficient PAC learnability of acyclic conjunctive queries
This note serves three purposes: (i) we provide a self-contained exposit...
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06/10/2022
Extremal Fitting Problems for Conjunctive Queries
The fitting problem for conjunctive queries (CQs) is the problem to cons...
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05/04/2022
Ontology-Mediated Querying on Databases of Bounded Cliquewidth
We study the evaluation of ontology-mediated queries (OMQs) on databases...
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04/29/2022
Frontiers and Exact Learning of ELI Queries under DL-Lite Ontologies
We study ELI queries (ELIQs) in the presence of ontologies formulated in...
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03/17/2022
Efficiently Enumerating Answers to Ontology-Mediated Queries
We study the enumeration of answers to ontology-mediated queries (OMQs) ...
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02/11/2022
Conservative Extensions for Existential Rules
We study the problem to decide, given sets T1,T2 of tuple-generating dep...
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07/12/2021
How to Approximate Ontology-Mediated Queries
We introduce and study several notions of approximation for ontology-med...
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07/12/2021
Separating Data Examples by Description Logic Concepts with Restricted Signatures
We study the separation of positive and negative data examples in terms ...
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05/18/2021
Actively Learning Concepts and Conjunctive Queries under ELr-Ontologies
We consider the problem to learn a concept or a query in the presence of...
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01/08/2021
Answer Counting under Guarded TGDs
We study the complexity of answer counting for ontology-mediated queries...
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11/19/2020
Conservative Extensions in Horn Description Logics with Inverse Roles
We investigate the decidability and computational complexity of conserva...
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11/19/2020
First Order-Rewritability and Containment of Conjunctive Queries in Horn Description Logics
We study FO-rewritability of conjunctive queries in the presence of onto...
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11/18/2020
First-Order Rewritability of Frontier-Guarded Ontology-Mediated Queries
We focus on ontology-mediated queries (OMQs) based on (frontier-)guarded...
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11/18/2020
Query Expressibility and Verification in Ontology-Based Data Access
In ontology-based data access, multiple data sources are integrated usin...
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10/22/2020
From Conjunctive Queries to Instance Queries in Ontology-Mediated Querying
We consider ontology-mediated queries (OMQs) based on expressive descrip...
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10/22/2020
Containment in Monadic Disjunctive Datalog, MMSNP, and Expressive Description Logics
We study query containment in three closely related formalisms: monadic ...
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07/06/2020
Separating Positive and Negative Data Examples by Concepts and Formulas: The Case of Restricted Signatures
We study the separation of positive and negative data examples in terms ...
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07/03/2020
Logical Separability of Incomplete Data under Ontologies
Finding a logical formula that separates positive and negative examples ...
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04/16/2020
Holding a Conference Online and Live due to COVID-19
The joint EDBT/ICDT conference (International Conference on Extending Da...
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03/17/2020
When is Ontology-Mediated Querying Efficient?
In ontology-mediated querying, description logic (DL) ontologies are use...
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01/21/2020
A Journey into Ontology Approximation: From Non-Horn to Horn
We study complete approximations of an ontology formulated in a non-Horn...
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01/21/2020
A Journey into Ontology Approximation: From Non-Horn to Hon
We study complete approximations of an ontology formulated in a non-Horn...
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12/28/2019
The Limits of Efficiency for Open- and Closed-World Query Evaluation Under Guarded TGDs
Ontology-mediated querying and querying in the presence of constraints a...
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04/29/2019
A Complete Classification of the Complexity and Rewritability of Ontology-Mediated Queries based on the Description Logic EL
We provide an ultimately fine-grained analysis of the data complexity an...
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01/31/2019
Query Inseparability for ALC Ontologies
We investigate the problem whether two ALC ontologies are indistinguisha...
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09/01/2018
The Data Complexity of Ontology-Mediated Queries with Closed Predicates
In the context of ontology-mediated querying with description logics (DL...
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04/26/2018
Weighted model counting beyond two-variable logic
It was recently shown by van den Broeck at al. that the symmetric weight...
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04/20/2018
Inseparability and Conservative Extensions of Description Logic Ontologies: A Survey
The question whether an ontology can safely be replaced by another, poss...
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04/18/2018
Computing FO-Rewritings in EL in Practice: from Atomic to Conjunctive Queries
A prominent approach to implementing ontology-mediated queries (OMQs) is...
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04/18/2018
Dichotomies in Ontology-Mediated Querying with the Guarded Fragment
We study the complexity of ontology-mediated querying when ontologies ar...
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09/20/2017
Exact Learning of Lightweight Description Logic Ontologies
We study the problem of learning description logic (DL) ontologies in An...
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11/08/2016
The Data Complexity of Description Logic Ontologies
We analyze the data complexity of ontology-mediated querying where the o...
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01/15/2014
The Complexity of Circumscription in DLs
As fragments of first-order logic, Description logics (DLs) do not provi...
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01/28/2013
Ontology-based Data Access: A Study through Disjunctive Datalog, CSP, and MMSNP
Ontology-based data access is concerned with querying incomplete data so...
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10/31/2011
Conjunctive Query Answering for the Description Logic SHIQ
Conjunctive queries play an important role as an expressive query langua...
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04/14/2011