All Outputs (26)

Depth lower bounds in Stabbing Planes for combinatorial principles (2024)
Journal Article
Dantchev, S., Galesi, N., Ghani, A., & Martin, B. (2024). Depth lower bounds in Stabbing Planes for combinatorial principles. Logical Methods in Computer Science, 20(1), 1-19. https://doi.org/10.46298/lmcs-20%281%3A1%292024

Stabbing Planes (also known as Branch and Cut) is a proof system introduced very recently which, informally speaking, extends the DPLL method by branching on integer linear inequalities instead of single variables. The techniques known so far to prov... Read More about Depth lower bounds in Stabbing Planes for combinatorial principles.

The Complexity of L(p, q)-Edge-Labelling (2023)
Journal Article
Berthe, G., Martin, B., Paulusma, D., & Smith, S. (2023). The Complexity of L(p, q)-Edge-Labelling. Algorithmica, https://doi.org/10.1007/s00453-023-01120-4

The L(p, q)-EDGE-LABELLING problem is the edge variant of the well-known L(p, q)-LABELLING problem. It is equivalent to the L(p, q)-LABELLING problem itself if we restrict the input of the latter problem to line graphs. So far, the complexity of L(p,... Read More about The Complexity of L(p, q)-Edge-Labelling.

Induced Disjoint Paths and Connected Subgraphs for H-Free Graphs (2023)
Journal Article
Martin, B., Paulusma, D., Smith, S., & van Leeuwen, E. J. (2023). Induced Disjoint Paths and Connected Subgraphs for H-Free Graphs. Algorithmica, 85, 2580–2604. https://doi.org/10.1007/s00453-023-01109-z

Paths P1,…,Pk in a graph G=(V,E) are mutually induced if any two distinct Pi and Pj have neither common vertices nor adjacent vertices. The INDUCED DISJOINT PATHS problem is to decide if a graph G with k pairs of specified vertices (si,ti) contains k... Read More about Induced Disjoint Paths and Connected Subgraphs for H-Free Graphs.

Few induced disjoint paths for H-free graphs (2022)
Journal Article
Martin, B., Paulusma, D., Smith, S., & van Leeuwen, E. (2023). Few induced disjoint paths for H-free graphs. Theoretical Computer Science, 939, 182-193. https://doi.org/10.1016/j.tcs.2022.10.024

Paths in a graph are mutually induced if any two distinct and have neither common vertices nor adjacent vertices. For a fixed integer k, the k-Induced Disjoint Paths problem is to decide if a graph G with k pairs of specified vertices contains k mutu... Read More about Few induced disjoint paths for H-free graphs.

The complexity of quantified constraints: collapsibility, switchability and the algebraic formulation (2022)
Journal Article
Carvalho, C., Madelaine, F., Martin, B., & Zhuk, D. (2023). The complexity of quantified constraints: collapsibility, switchability and the algebraic formulation. ACM Transactions on Computational Logic, 24(1), Article 5. https://doi.org/10.1145/3568397

Let A be an idempotent algebra on a finite domain. By mediating between results of Chen [1] and Zhuk [2], we argue that if A satisfies the polynomially generated powers property (PGP) and B is a constraint language invariant under A (that is, in Inv(... Read More about The complexity of quantified constraints: collapsibility, switchability and the algebraic formulation.

Colouring generalized claw-free graphs and graphs of large girth: Bounding the diameter (2022)
Journal Article
Martin, B., Paulusma, D., & Smith, S. (2022). Colouring generalized claw-free graphs and graphs of large girth: Bounding the diameter. Theoretical Computer Science, 931, 104-116. https://doi.org/10.1016/j.tcs.2022.07.034

For a fixed integer, the k-Colouring problem is to decide if the vertices of a graph can be coloured with at most k colours for an integer k, such that no two adjacent vertices are coloured alike. A graph G is H-free if G does not contain H as an ind... Read More about Colouring generalized claw-free graphs and graphs of large girth: Bounding the diameter.

Partitioning H-free graphs of bounded diameter (2022)
Journal Article
Brause, C., Golovach, P., Martin, B., Paulusma, D., & Smith, S. (2022). Partitioning H-free graphs of bounded diameter. Theoretical Computer Science, 930, 37-52. https://doi.org/10.1016/j.tcs.2022.07.009

A natural way of increasing our understanding of NP-complete graph problems is to restrict the input to a special graph class. Classes of H-free graphs, that is, graphs that do not contain some graph H as an induced subgraph, have proven to be an ide... Read More about Partitioning H-free graphs of bounded diameter.

Acyclic, Star, and Injective Colouring: Bounding the diameter (2022)
Journal Article
Brause, C., Golovach, P., Martin, B., Ochem, P., Paulusma, D., & Smith, S. (2022). Acyclic, Star, and Injective Colouring: Bounding the diameter. Electronic Journal of Combinatorics, 29(2), https://doi.org/10.37236/10738

We examine the effect of bounding the diameter for a number of natural and well-studied variants of the COLOURING problem. A colouring is acyclic, star, or injective if any two colour classes induce a forest, star forest or disjoint union of vertices... Read More about Acyclic, Star, and Injective Colouring: Bounding the diameter.

QCSP on reflexive tournaments (2022)
Journal Article
Larose, B., Martin, B., Markovic, P., Paulusma, D., Smith, S., & Zivny, S. (2022). QCSP on reflexive tournaments. ACM Transactions on Computational Logic, 23(3), 1-22. https://doi.org/10.1145/3508069

We give a complexity dichotomy for the Quantified Constraint Satisfaction Problem QCSP(H) when H is a reflexive tournament. It is well known that reflexive tournaments can be split into a sequence of strongly connected components H1,…,Hn so that ther... Read More about QCSP on reflexive tournaments.

Colouring graphs of bounded diameter in the absence of small cycles (2022)
Journal Article
Martin, B., Paulusma, D., & Smith, S. (2022). Colouring graphs of bounded diameter in the absence of small cycles. Discrete Applied Mathematics, 314, 150-161. https://doi.org/10.1016/j.dam.2022.02.026

For k ≥ 1, a k-colouring c of G is a mapping from V (G) to {1, 2, . . . , k} such that c(u) 6= c(v) for any two adjacent vertices u and v. The k-Colouring problem is to decide if a graph G has a k-colouring. For a family of graphs H, a graph G is H-f... Read More about Colouring graphs of bounded diameter in the absence of small cycles.

The lattice and semigroup structure of multipermutations (2021)
Journal Article
Carvalho, C., & Martin, B. (2022). The lattice and semigroup structure of multipermutations. International Journal of Algebra and Computation, 32(2), 211-235. https://doi.org/10.1142/s0218196722500096

We study the algebraic properties of binary relations whose underlying digraph is smooth, that is, has no source or sink. Such objects have been studied as surjective hyper-operations (shops) on the corresponding vertex set, and as binary relations t... Read More about The lattice and semigroup structure of multipermutations.

Disjoint paths and connected subgraphs for H-free graphs (2021)
Journal Article
Kern, W., Martin, B., Paulusma, D., Smith, S., & van Leeuwen, E. (2022). Disjoint paths and connected subgraphs for H-free graphs. Theoretical Computer Science, 898, 59-68. https://doi.org/10.1016/j.tcs.2021.10.019

The well-known Disjoint Paths problem is to decide if a graph contains k pairwise disjoint paths, each connecting a different terminal pair from a set of k distinct vertex pairs. We determine, with an exception of two cases, the complexity of the Dis... Read More about Disjoint paths and connected subgraphs for H-free graphs.

Hard problems that quickly become very easy (2021)
Journal Article
Martin, B., Paulusma, D., & Smith, S. (2022). Hard problems that quickly become very easy. Information Processing Letters, 174, https://doi.org/10.1016/j.ipl.2021.106213

A graph class is hereditary if it is closed under vertex deletion. We give examples of NP-hard, PSPACE-complete and NEXPTIME-complete problems that become constant-time solvable for every hereditary graph class that is not equal to the class of all g... Read More about Hard problems that quickly become very easy.

Disconnected cuts in claw-free graphs (2020)
Journal Article
Martin, B., Paulusma, D., & van Leeuwen, E. (2020). Disconnected cuts in claw-free graphs. Journal of Computer and System Sciences, 113, 60-75. https://doi.org/10.1016/j.jcss.2020.04.005

A disconnected cut of a connected graph is a vertex cut that itself also induces a disconnected subgraph. The corresponding decision problem is called Disconnected Cut. This problem is known to be NP-hard on general graphs. We prove that it is polyno... Read More about Disconnected cuts in claw-free graphs.

Constraint satisfaction problems for reducts of homogeneous graphs (2019)
Journal Article
Bodirsky, M., Martin, B., Pinsker, M., & Pongracz, A. (2019). Constraint satisfaction problems for reducts of homogeneous graphs. SIAM Journal on Computing, 48(4), 1224-1264. https://doi.org/10.1137/16m1082974

For $n\geq 3$, let $(H_n, E)$ denote the $n$th Henson graph, i.e., the unique countable homogeneous graph with exactly those finite graphs as induced subgraphs that do not embed the complete graph on $n$ vertices. We show that for all structures $\Ga... Read More about Constraint satisfaction problems for reducts of homogeneous graphs.

Surjective H-Colouring over reflexive digraphs (2018)
Journal Article
Larose, B., Martin, B., & Paulusma, D. (2018). Surjective H-Colouring over reflexive digraphs. ACM Transactions on Computation Theory, 11(1), Article 3. https://doi.org/10.1145/3282431

The Surjective H-Colouring problem is to test if a given graph allows a vertex-surjective homomorphism to a fixed graph H. The complexity of this problem has been well studied for undirected (partially) reflexive graphs. We introduce endo-triviality,... Read More about Surjective H-Colouring over reflexive digraphs.

On the Complexity of the Model Checking Problem (2018)
Journal Article
Madelaine, F. R., & Martin, B. D. (2018). On the Complexity of the Model Checking Problem. SIAM Journal on Computing, 47(3), 769-797. https://doi.org/10.1137/140965715

The complexity of the model checking problem for various fragments of first-order logic (FO) has attracted much attention over the last two decades, in particular for the fragment induced by ∃ and ∧ and that induced by ∀, ∃, and ∧, which are better k... Read More about On the Complexity of the Model Checking Problem.

Surjective H-colouring: New hardness results (2018)
Journal Article
Golovach, P., Johnson, M., Martin, B., Paulusma, D., & Stewart, A. (2019). Surjective H-colouring: New hardness results. Computability, 8(1), 27-42. https://doi.org/10.3233/com-180084

A homomorphism from a graph G to a graph H is a vertex mapping f from the vertex set of G to the vertex set of H such that there is an edge between vertices f(u) and f(v) of H whenever there is an edge between vertices u and v of G. The H-Colouring p... Read More about Surjective H-colouring: New hardness results.

Discrete Temporal Constraint Satisfaction Problems (2018)
Journal Article
Bodirsky, M., Martin, B., & Mottet, A. (2018). Discrete Temporal Constraint Satisfaction Problems. Journal of the ACM, 65(2), Article 9. https://doi.org/10.1145/3154832

A discrete temporal constraint satisfaction problem is a constraint satisfaction problem (CSP) over the set of integers whose constraint language consists of relations that are first-order definable over the order of the integers. We prove that every... Read More about Discrete Temporal Constraint Satisfaction Problems.

Circuit Satisfiability and Constraint Satisfaction around Skolem Arithmetic (2017)
Journal Article
Glaßer, C., Jonsson, P., & Martin, B. (2017). Circuit Satisfiability and Constraint Satisfaction around Skolem Arithmetic. Theoretical Computer Science, 703, 18-36. https://doi.org/10.1016/j.tcs.2017.08.025

We study interactions between Skolem Arithmetic and certain classes of Circuit Satisfiability and Constraint Satisfaction Problems (CSPs). We revisit results of Glaßer et al. [1] in the context of CSPs and settle the major open question from that pap... Read More about Circuit Satisfiability and Constraint Satisfaction around Skolem Arithmetic.