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A Dichotomy Theorem for Nonuniform CSPs

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TLDR
In this paper, the authors confirm the Dichotomy Conjecture for the non-uniform CSP, which states that for every constraint language \Gm the problem is either solvable in polynomial time or is NP-complete.
Abstract
In a non-uniform Constraint Satisfaction problem CSP(Γ), where G is a set of relations on a finite set A, the goal is to find an assignment of values to variables subject to constraints imposed on specified sets of variables using the relations from Γ. The Dichotomy Conjecture for the non-uniform CSP states that for every constraint language \Gm the problem CSP(Γ) is either solvable in polynomial time or is NP-complete. It was proposed by Feder and Vardi in their seminal 1993 paper. In this paper we confirm the Dichotomy Conjecture.

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Citations
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Journal Article

Towards a Data Complexity Classification of Ontology-Mediated Queries with Covering.

TL;DR: A number of new syntactic and semantic sufficient and necessary conditions for ontology-mediated queries (OMQs) are proved with one covering axiom to be in the classes AC and NL for data complexity, and to be L-, NLor P-hard.
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The Data Complexity of Ontology-Mediated Queries with Closed Predicates

TL;DR: This work provides a non-uniform analysis, aiming at a classification of the complexity into tractable and non-tractable for ontologies in the lightweight DLs DL-Lite and EL, and the expressive DL ALCHI, and shows that there is no dichotomy if both concept and role names can be closed.
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Combinatorial Gap Theorem and Reductions between Promise CSPs.

TL;DR: In this article, the gap theorem implies NP-hardness of a gap version of the Layered Label Cover Problem (LCCP), and a sufficient condition under which a fixed template constraint satisfaction problem (PCSP) reduces to another PCSP is provided.
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Combinatorial Gap Theorem and Reductions between Promise CSPs

TL;DR: In this article , Barto et al. showed that the gap theorem implies NP-hardness of a gap version of the LBCP, which is known as the Layered Label Cover Problem.
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Permutation groups with small orbit growth

TL;DR: In this article, it was shown that the class of first-order reducts of finite covers of unary structures is closed under taking model companions and model-complete cores.
References
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On the complexity of H -coloring

TL;DR: The natural conjecture, formulated in several sources, asserts that the H-coloring problem is NP-complete for any non-bipartite graph H, and a proof of this conjecture is given.
Journal ArticleDOI

Classifying the Complexity of Constraints Using Finite Algebras

TL;DR: It is shown that any set of relations used to specify the allowed forms of constraints can be associated with a finite universal algebra and how the computational complexity of the corresponding constraint satisfaction problem is connected to the properties of this algebra is explored.
Journal ArticleDOI

Undirected connectivity in log-space

TL;DR: A deterministic, log-space algorithm that solves st-connectivity in undirected graphs and implies a way to construct in log- space a fixed sequence of directions that guides a deterministic walk through all of the vertices of any connected graph.
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