1 code implementation • 20 Nov 2018 • Wolfgang Fischl, Georg Gottlob, Davide M. Longo, Reinhard Pichler
To cope with the intractability of answering Conjunctive Queries (CQs) and solving Constraint Satisfaction Problems (CSPs), several notions of hypergraph decompositions have been proposed -- giving rise to different notions of width, noticeably, plain, generalized, and fractional hypertree width (hw, ghw, and fhw).
Databases
2 code implementations • 3 Nov 2016 • Wolfgang Fischl, Georg Gottlob, Reinhard Pichler
It is known that hw(H) <= k can be checked in polynomial time for fixed k, while checking ghw(H) <= k is NP-complete for any k greater than or equal to 3.
Databases Computational Complexity
1 code implementation • 14 Jan 2007 • Georg Gottlob, Marko Samer
Hypertree decompositions of hypergraphs are a generalization of tree decompositions of graphs.
1 code implementation • 2 Sep 2020 • Wolfgang Fischl, Georg Gottlob, Davide Mario Longo, Reinhard Pichler
To cope with the intractability of answering Conjunctive Queries (CQs) and solving Constraint Satisfaction Problems (CSPs), several notions of hypergraph decompositions have been proposed -- giving rise to different notions of width, noticeably, plain, generalized, and fractional hypertree width (hw, ghw, and fhw).
no code implementations • 17 Mar 2018 • Leopoldo Bertossi, Georg Gottlob, Reinhard Pichler
This use of Datalog$^\pm$ is extended to give a set semantics to duplicates in Datalog$^\pm$ itself.
no code implementations • 14 Nov 2017 • Georg Gottlob, Gianlugi Greco, Francesco Scarcello
Solution methods have therefore been proposed in the literature that do not require a tree projection to be given, and that either correctly decide whether the given CSP instance is satisfiable, or return that a tree projection actually does not exist.
no code implementations • 9 Dec 2012 • Georg Gottlob
The monotone duality problem is defined as follows: Given two monotone formulas f and g in iredundant DNF, decide whether f and g are dual.
no code implementations • 23 Jul 2018 • Luigi Bellomarini, Ruslan R. Fayzrakhmanov, Georg Gottlob, Andrey Kravchenko, Eleonora Laurenza, Yavor Nenov, Stephane Reissfelder, Emanuel Sallinger, Evgeny Sherkhonov, Lianlong Wu
Following the recent successful examples of large technology companies, many modern enterprises seek to build knowledge graphs to provide a unified view of corporate knowledge and to draw deep insights using machine learning and logical reasoning.
no code implementations • 23 Jul 2018 • Luigi Bellomarini, Georg Gottlob, Emanuel Sallinger
Yet, Datalog-based reasoning in the presence of existential quantification is in general undecidable.
no code implementations • 16 Sep 2018 • Gerald Berger, Georg Gottlob, Andreas Pieris, Emanuel Sallinger
Vadalog is a system for performing complex reasoning tasks such as those required in advanced knowledge graphs.
no code implementations • 29 Dec 2020 • Georg Gottlob, Matthias Lanzinger, Davide Mario Longo, Cem Okulmus, Reinhard Pichler
Constraint Satisfaction Problems (CSPs) play a central role in many applications in Artificial Intelligence and Operations Research.
no code implementations • 7 Oct 2021 • Andrei Draghici, Georg Gottlob, Matthias Lanzinger
We investigate the computational complexity of mining guarded clauses from clausal datasets through the framework of inductive logic programming (ILP).
no code implementations • 22 Apr 2022 • Marco Calautti, Georg Gottlob, Andreas Pieris
In this context, a key problem is non-uniform chase termination: does the chase of a database w. r. t.
1 code implementation • 21 Sep 2022 • Georg Gottlob, Matthias Lanzinger, Davide Mario Longo, Cem Okulmus
As decompositions can be reused to solve CSPs with the same constraint scopes, investing resources in computing good decompositions is beneficial, even though the computation itself is hard.
no code implementations • 4 Nov 2002 • Nicola Leone, Gerald Pfeifer, Wolfgang Faber, Thomas Eiter, Georg Gottlob, Simona Perri, Francesco Scarcello
As for problem solving, we provide a formal definition of its kernel language, function-free disjunctive logic programs (also known as disjunctive datalog), extended by weak constraints, which are a powerful tool to express optimization problems.
no code implementations • 8 Feb 2024 • Lingzhi Wang, Xingshan Zeng, Jinsong Guo, Kam-Fai Wong, Georg Gottlob
The aim of this study is to investigate Machine Unlearning (MU), a burgeoning field focused on addressing concerns related to neural models inadvertently retaining personal or sensitive data.
no code implementations • 5 Mar 2024 • Matthias Lanzinger, Stefano Sferrazza, Przemysław A. Wałęga, Georg Gottlob
One of the main challenges in the area of Neuro-Symbolic AI is to perform logical reasoning in the presence of both neural and symbolic data.