no code implementations • 14 Jan 2020 • Henrik Forssell, Evgeny Kharlamov, Evgenij Thorstensen
However, for Closed Powerset semantics we show that one can find, for any incomplete database, a unique finite set of its subinstances which are subinstances (up to renaming of nulls) of all instances semantically equivalent to the original incomplete one.
no code implementations • 27 Sep 2018 • Henrik Forssell, Christian Kindermann, Daniel P. Lupp, Uli Sattler, Evgenij Thorstensen
We present a second-order language that can be used to succinctly specify ontologies in a consistent and transparent manner.
no code implementations • 7 Jul 2016 • Daniel P. Lupp, Evgenij Thorstensen
In ontology-based data access, databases are connected to an ontology via mappings from queries over the database to queries over the ontology.
no code implementations • 9 Feb 2015 • Evgenij Thorstensen
We show that when the number of solutions to a CSP instance is bounded in key parts of the problem, structural restrictions can be used to derive new tractable classes.
no code implementations • 10 Jul 2013 • David A. Cohen, Peter G. Jeavons, Evgenij Thorstensen, Stanislav Živný
We study the complexity of constraint satisfaction problems involving global constraints, i. e., special-purpose constraints provided by a solver and represented implicitly by a parametrised algorithm.
no code implementations • 6 Jul 2013 • Evgenij Thorstensen
This allows us to lift these restrictions to the global case, and identify new tractable classes of CSPs with global constraints.