Professor Daniel Paulusma's Outputs (25)

Detecting induced minors in AT-free graphs (2012)
Presentation / Conference Contribution
Golovach, P. A., Kratsch, D., & Paulusma, D. (2012, December). Detecting induced minors in AT-free graphs

The problem Induced Minor is to test whether a graph G can be modified into a graph H by a sequence of vertex deletions and edge contractions. We prove that Induced Minor is polynomial-time solvable when G is AT-free, and H is fixed, i.e., not part o... Read More about Detecting induced minors in AT-free graphs.

Obtaining planarity by contracting few edges (2012)
Presentation / Conference Contribution
Golovach, P. A., van 't Hog, P., & Paulusma, D. (2012, December). Obtaining planarity by contracting few edges

The Planar Contraction problem is to test whether a given graph can be made planar by using at most k edge contractions. This problem is known to be NP-complete. We show that it is fixed-parameter tractable when parameterized by k.

Finding vertex-surjective graph homomorphisms (2012)
Presentation / Conference Contribution
Golovach, P. A., Lidicky, B., Martin, B., & Paulusma, D. (2012, December). Finding vertex-surjective graph homomorphisms

The Surjective Homomorphism problem is to test whether a given graph G called the guest graph allows a vertex-surjective homomorphism to some other given graph H called the host graph. The bijective and injective homomorphism problems can be formulat... Read More about Finding vertex-surjective graph homomorphisms.

Closing complexity gaps for coloring problems on H-free graphs (2012)
Presentation / Conference Contribution
Golovach, P. A., Paulusma, D., & Song, J. (2012, December). Closing complexity gaps for coloring problems on H-free graphs

If a graph G contains no subgraph isomorphic to some graph H, then G is called H-free. A coloring of a graph G = (V,E) is a mapping c: V → {1,2,…} such that no two adjacent vertices have the same color, i.e., c(u) ≠ c(v) if uv ∈ E; if |c(V)| ≤ k then... Read More about Closing complexity gaps for coloring problems on H-free graphs.

Induced disjoint paths in claw-free graphs (2012)
Presentation / Conference Contribution
Golovach, P. A., Paulusma, D., & van Leeuwen, E. J. (2012, December). Induced disjoint paths in claw-free graphs

Paths P1,…,Pk in a graph G = (V,E) are said to be mutually induced if for any 1 ≤ i < j ≤ k, Pi and Pj have neither common vertices nor adjacent vertices (except perhaps their end-vertices). The Induced Disjoint Paths problem is to test whether a gra...

Induced disjoint paths in AT-free graphs (2012)
Presentation / Conference Contribution
Golovach, P. A., Paulusma, D., & van Leeuwen, E. J. (2012, December). Induced disjoint paths in AT-free graphs

Paths P1,…,Pk in a graph G = (V,E) are said to be mutually induced if for any 1 ≤ i < j ≤ k, Pi and Pj have neither common vertices nor adjacent vertices (except perhaps their end-vertices). The Induced Disjoint Paths problem is to test whether a gra...

Solutions for the stable rommates problem with payments (2012)
Presentation / Conference Contribution
Biró, P., Bomhoff, M., Golovach, P. A., Kern, W., & Paulusma, D. (2012, December). Solutions for the stable rommates problem with payments

The stable roommates problem with payments has as input a graph G = (V,E) with an edge weighting w: E → ℝ +  and the problem is to find a stable solution. A solution is a matching M with a vector p∈R V + that satisfies pu + pv = w(uv) for all uv ∈ M... Read More about Solutions for the stable rommates problem with payments.

Coloring graphs characterized by a forbidden subgraph (2012)
Presentation / Conference Contribution
Golovach, P. A., Paulusma, D., & Ries, B. (2012, December). Coloring graphs characterized by a forbidden subgraph

The Coloring problem is to test whether a given graph can be colored with at most k colors for some given k, such that no two adjacent vertices receive the same color. The complexity of this problem on graphs that do not contain some graph H as an in... Read More about Coloring graphs characterized by a forbidden subgraph.

4-Coloring H-free graphs when H is small (2012)
Presentation / Conference Contribution
Golovach, P., Paulusma, D., & Song, J. (2012, December). 4-Coloring H-free graphs when H is small

The k-Coloring problem is to test whether a graph can be colored with at most k colors such that no two adjacent vertices receive the same color. If a graph G does not contain a graph H as an induced subgraph, then G is called H-free. For any fixed g... Read More about 4-Coloring H-free graphs when H is small.

How to eliminate a graph (2012)
Presentation / Conference Contribution
Golovach, P., Heggernes, P., van 't Hof, P., Manne, F., Paulusma, D., & Pilipczuk, M. (2012, December). How to eliminate a graph

Vertex elimination is a graph operation that turns the neighborhood of a vertex into a clique and removes the vertex itself. It has widely known applications within sparse matrix computations. We define the Elimination problem as follows: given two g... Read More about How to eliminate a graph.

Characterizing graphs of small carving-width (2012)
Presentation / Conference Contribution
Belmonte, R., van 't Hof, P., Kaminski, M., Paulusma, D., & Thilikos, D. (2012, December). Characterizing graphs of small carving-width

We characterize all graphs that have carving-width at most k for k = 1,2,3. In particular, we show that a graph has carving-width at most 3 if and only if it has maximum degree at most 3 and treewidth at most 2. This enables us to identify the immers... Read More about Characterizing graphs of small carving-width.

Detecting induced star-like minors in polynomial time (2012)
Journal Article
Fiala, J., Kaminksi, M., & Paulusma, D. (2012). Detecting induced star-like minors in polynomial time. Journal of discrete algorithms, 17, 74-85. https://doi.org/10.1016/j.jda.2012.11.002

The Induced Minor problem is to test whether a graph G contains a graph H as an induced minor, i.e., if G can be modified into H by a sequence of vertex deletions and edge contractions. When H is fixed, i.e., not part of the input, this problem is de... Read More about Detecting induced star-like minors in polynomial time.

Computing vertex-surjective homomorphisms to partially reflexive trees (2012)
Journal Article
Golovach, P., Paulusma, D., & Song, J. (2012). Computing vertex-surjective homomorphisms to partially reflexive trees. Theoretical Computer Science, 457, 86-100. https://doi.org/10.1016/j.tcs.2012.06.039

A homomorphism from a graph GG to a graph HH is a vertex mapping f:VG→VHf:VG→VH such that f(u)f(u) and f(v)f(v) form an edge in HH whenever uu and vv form an edge in GG. The HH-Coloring problem is that of testing whether a graph GG allows a homomorph... Read More about Computing vertex-surjective homomorphisms to partially reflexive trees.

Finding vertex-surjective graph homomorphisms (2012)
Journal Article
Golovach, P., Lidicky, B., Martin, B., & Paulusma, D. (2012). Finding vertex-surjective graph homomorphisms. Acta Informatica, 49(6), 381-394. https://doi.org/10.1007/s00236-012-0164-0

The Surjective Homomorphism problem is to test whether a given graph G called the guest graph allows a vertex-surjective homomorphism to some other given graph H called the host graph. The bijective and injective homomorphism problems can be formulat... Read More about Finding vertex-surjective graph homomorphisms.

On the parameterized complexity of coloring graphs in the absence of a linear forest (2012)
Journal Article
Couturier, J., Golovach, P., Kratsch, D., & Paulusma, D. (2012). On the parameterized complexity of coloring graphs in the absence of a linear forest. Journal of discrete algorithms, 15, 56-62. https://doi.org/10.1016/j.jda.2012.04.008

The k-Coloring problem is to decide whether a graph can be colored with at most k colors such that no two adjacent vertices receive the same color. The Listk-Coloring problem requires in addition that every vertex u must receive a color from some giv... Read More about On the parameterized complexity of coloring graphs in the absence of a linear forest.

Computing role assignments of proper interval graphs in polynomial time (2012)
Journal Article
Heggernes, P., van 't Hof, P., & Paulusma, D. (2012). Computing role assignments of proper interval graphs in polynomial time. Journal of discrete algorithms, 14, 173-188. https://doi.org/10.1016/j.jda.2011.12.004

An R-role assignment of a graph G is a locally surjective homomorphism from G to graph R. For a fixed graph R, the R-Role Assignment problem is to decide, for an input graph G, whether G has an R-role assignment. When both graphs G and R are given as... Read More about Computing role assignments of proper interval graphs in polynomial time.

Distance three labelings of trees (2012)
Journal Article
Fiala, J., Golovach, P., Kratochvil, J., Lidický, B., & Paulusma, D. (2012). Distance three labelings of trees. Discrete Applied Mathematics, 160(6), 764-779. https://doi.org/10.1016/j.dam.2011.02.004

An L(2,1,1)-labeling of a graph G assigns nonnegative integers to the vertices of G in such a way that labels of adjacent vertices differ by at least two, while vertices that are at distance at most three are assigned different labels. The maximum la... Read More about Distance three labelings of trees.

On graph contractions and induced minors (2012)
Journal Article
Hof, P. V. '., Kaminski, M., Paulusma, D., Szeider, S., & Thilikos, D. (2012). On graph contractions and induced minors. Discrete Applied Mathematics, 160(6), 799-809. https://doi.org/10.1016/j.dam.2010.05.005

The Induced Minor Containment problem takes as input two graphs G and H, and asks whether G has H as an induced minor. We show that this problem is fixed parameter tractable in |VH| if G belongs to any nontrivial minor-closed graph class and H is a p... Read More about On graph contractions and induced minors.

Determining the chromatic number of triangle-free 2P3-free graphs in polynomial time (2012)
Journal Article
Broersma, H., Golovach, P., Paulusma, D., & Song, J. (2012). Determining the chromatic number of triangle-free 2P3-free graphs in polynomial time. Theoretical Computer Science, 423, 1-10. https://doi.org/10.1016/j.tcs.2011.12.076

Let 2P3 denote the disjoint union of two paths on three vertices. A graph G that has no subgraph isomorphic to a graph H is called H-free. The Vertex Coloring problem is the problem to determine the chromatic number of a graph. Its computational comp... Read More about Determining the chromatic number of triangle-free 2P3-free graphs in polynomial time.

Induced packing of odd cycles in planar graphs (2012)
Journal Article
Golovach, P., Kamiński, M., Paulusma, D., & Thilikos, D. (2012). Induced packing of odd cycles in planar graphs. Theoretical Computer Science, 420, 28-35. https://doi.org/10.1016/j.tcs.2011.11.004

An induced packing of odd cycles in a graph is a packing such that there is no edge in the graph between any two odd cycles in the packing. We prove that an induced packing of k odd cycles in an n-vertex graph can be found (if it exists) in time 2O(k... Read More about Induced packing of odd cycles in planar graphs.