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Dive into the research topics where Henning Fernau is active.

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Featured researches published by Henning Fernau.


Algorithmica | 2002

Fixed Parameter Algorithms for DOMINATING SET and Related Problems on Planar Graphs

Jochen Alber; Hans L. Bodlaender; Henning Fernau; Ton Kloks; Rolf Niedermeier

Abstract. We present an algorithm that constructively produces a solution to the k -DOMINATING SET problem for planar graphs in time O(c^ \sqrt k n) , where c=4^ 6\sqrt 34 . To obtain this result, we show that the treewidth of a planar graph with domination number γ (G) is O(\sqrt \rule 0pt 4pt \smash γ (G) ) , and that such a tree decomposition can be found in O(\sqrt \rule 0pt 4pt \smash γ (G) n) time. The same technique can be used to show that the k -FACE COVER problem (find a size k set of faces that cover all vertices of a given plane graph) can be solved in O(c1^ \sqrt k n) time, where c1=3^ 36\sqrt 34 and k is the size of the face cover set. Similar results can be obtained in the planar case for some variants of k -DOMINATING SET, e.g., k -INDEPENDENT DOMINATING SET and k -WEIGHTED DOMINATING SET.


SIAM Journal on Computing | 2007

Parametric Duality and Kernelization: Lower Bounds and Upper Bounds on Kernel Size

Jianer Chen; Henning Fernau; Iyad A. Kanj; Ge Xia

Determining whether a parameterized problem is kernelizable and has a small kernel size has recently become one of the most interesting topics of research in the area of parameterized complexity and algorithms. Theoretically, it has been proved that a parameterized problem is kernelizable if and only if it is fixed-parameter tractable. Practically, applying a data reduction algorithm to reduce an instance of a parameterized problem to an equivalent smaller instance (i.e., a kernel) has led to very efficient algorithms and now goes hand-in-hand with the design of practical algorithms for solving


ACM Transactions on Algorithms | 2012

Kernel(s) for problems with no kernel: On out-trees with many leaves

Daniel Binkele-Raible; Henning Fernau; Fedor V. Fomin; Daniel Lokshtanov; Saket Saurabh; Yngve Villanger

\mathcal{NP}


scandinavian workshop on algorithm theory | 2000

Fixed Parameter Algorithms for PLANAR DOMINATING SET and Related Problems

Jochen Alber; Hans L. Bodlaender; Henning Fernau; Rolf Niedermeier

-hard problems. Well-known examples of such parameterized problems include the vertex cover problem, which is kernelizable to a kernel of size bounded by


IWPEC'06 Proceedings of the Second international conference on Parameterized and Exact Computation | 2006

EDGE DOMINATING SET: efficient enumeration-based exact algorithms

Henning Fernau

2k


Journal of Computer and System Sciences | 2003

Graph separators: a parameterized view

Jochen Alber; Henning Fernau; Rolf Niedermeier

, and the planar dominating set problem, which is kernelizable to a kernel of size bounded by


Algorithmica | 2010

A Top-Down Approach to Search-Trees: Improved Algorithmics for 3-Hitting Set

Henning Fernau

335k


Journal of Discrete Algorithms | 2009

Vertex and edge covers with clustering properties: Complexity and algorithms

Henning Fernau; David F. Manlove

. In this paper we develop new techniques to derive upper and lower bounds on the kernel size for certain parameterized problems. In terms of our lower bound results, we show, for example, that unless


computing and combinatorics conference | 2002

On Parameterized Enumeration

Henning Fernau

\mathcal{P} = \mathcal{NP}


mathematical foundations of computer science | 2001

Refined Search Tree Technique for DOMINATING SET on Planar Graphs

Jochen Alber; Hongbing Fan; Michael R. Fellows; Henning Fernau; Rolf Niedermeier; Frances A. Rosamond; Ulrike Stege

, planar vertex cover does not have a problem kernel of size smaller than

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Rudolf Freund

Vienna University of Technology

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Rolf Niedermeier

Technical University of Berlin

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Henning Bordihn

Otto-von-Guericke University Magdeburg

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