Without proposing a new key assignment scheme, this paper presents a graph translation procedure so that more complicated non-hierarchical access control policies can be enforced by existing hierarchical key assignmen...
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Without proposing a new key assignment scheme, this paper presents a graph translation procedure so that more complicated non-hierarchical access control policies can be enforced by existing hierarchical key assignment schemes. Published by Elsevier B.V.
This paper presents a new distributed self-stabilizing algorithm for the weakly connected minimal dominating set problem. It assumes a self-stabilizing algorithm to compute a breadth-first tree. Using an unfair distri...
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This paper presents a new distributed self-stabilizing algorithm for the weakly connected minimal dominating set problem. It assumes a self-stabilizing algorithm to compute a breadth-first tree. Using an unfair distributed scheduler the algorithm stabilizes in at most O (nmA) moves, where A is the number of moves to construct a breadth-first tree. All previously known algorithms required an exponential number of moves. (C) 2009 Elsevier B.V. All rights reserved.
We present a polynomial-time approximation algorithm for legally coloring as many edges of a given simple graph as possible using two colors. It achieves an approximation ratio of 24/29 approximate to 0.828. (C) 2009 ...
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We present a polynomial-time approximation algorithm for legally coloring as many edges of a given simple graph as possible using two colors. It achieves an approximation ratio of 24/29 approximate to 0.828. (C) 2009 Elsevier B.V. All rights reserved.
We present a bound of m/5.769 vertical bar O(log n) on the pathwidth of graphs with m edges. Respective path decompositions can be computed in polynomial time. Using a well-known framework for algorithms that rely on ...
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We present a bound of m/5.769 vertical bar O(log n) on the pathwidth of graphs with m edges. Respective path decompositions can be computed in polynomial time. Using a well-known framework for algorithms that rely on tree decompositions, this directly leads to runtime bounds of O*(2(m/5.769)) for Max-2SAT and Max-Cut. Both algorithms require exponential space due to dynamic programming. If we agree to accept a slightly larger bound of m/5.217 + 3, we even obtain path decompositions with a rather simple structure: all bags share a large set of common nodes. Using branching based algorithms, this allows us to solve the same problems in polynomial space and time O*(2(m/5.217)).
In [A. Garcia, C. Hernando, F. Hurtado, M. Noy, J. Tejel, Packing trees into planar graphs, J. graph Theory (2002) 172-181] Garcia et al. conjectured that for every two non-star trees there exists a planar graph conta...
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In [A. Garcia, C. Hernando, F. Hurtado, M. Noy, J. Tejel, Packing trees into planar graphs, J. graph Theory (2002) 172-181] Garcia et al. conjectured that for every two non-star trees there exists a planar graph containing them as edge-disjoint subgraphs. In this paper we prove the conjecture in the case in which one of the trees is a spider tree. (C) 2008 Elsevier B.V. All rights reserved.
We establish a necessary and sufficient condition for the existence of a factorization of the complete bipartite graph K(n,n) into some families of 3-regular graphs. (C) 2009 Elsevier B.V. All rights reserved.
We establish a necessary and sufficient condition for the existence of a factorization of the complete bipartite graph K(n,n) into some families of 3-regular graphs. (C) 2009 Elsevier B.V. All rights reserved.
Coja-Oghlan and Taraz [Amin Coja-Oghlan, Anusch Taraz, Exact and approximative algorithms for coloring G(n, p), Random Structures and algorithms 24 (3) (2004) 259-278] presented a graph coloring algorithm that has exp...
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Coja-Oghlan and Taraz [Amin Coja-Oghlan, Anusch Taraz, Exact and approximative algorithms for coloring G(n, p), Random Structures and algorithms 24 (3) (2004) 259-278] presented a graph coloring algorithm that has expected linear running time for random graphs with edge probability p satisfying np <= 1.01. In this work, we develop their analysis by exploiting generating function techniques. We show that, in fact, their algorithm colors G(n,p) with the minimal number of colors and has expected linear running time, provided that np <= 1.33. (C) 2008 Elsevier B.V. All rights reserved.
In this note we present a necessary and sufficient condition for a permutation to be t-complementing which is a natural generalization of the well-known result concerning self-complementing permutations. (C) 2009 Else...
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In this note we present a necessary and sufficient condition for a permutation to be t-complementing which is a natural generalization of the well-known result concerning self-complementing permutations. (C) 2009 Elsevier B.V. All rights reserved.
We present an algorithm to find a Hamiltonian cycle in a proper interval graph in O(m + n) time, where m is the number of edges and n is the number of vertices in the graph. The algorithm is simpler and shorter than p...
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We present an algorithm to find a Hamiltonian cycle in a proper interval graph in O(m + n) time, where m is the number of edges and n is the number of vertices in the graph. The algorithm is simpler and shorter than previous algorithms for the problem. (C) 2009 Elsevier B.V. All rights reserved.
We study the problems to find a maximum packing of shortest edge-disjoint cycles in a graph of given girth g (g-ESCP) and its vertex-disjoint analogue g-VSCP. In the case g = 3, Caprara and Rizzi (2001) have shown tha...
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We study the problems to find a maximum packing of shortest edge-disjoint cycles in a graph of given girth g (g-ESCP) and its vertex-disjoint analogue g-VSCP. In the case g = 3, Caprara and Rizzi (2001) have shown that g-ESCP can be solved in polynomial time for graphs with maximum degree 4, but is APX-hard for graphs with maximum degree 5, while g-VSCP can be solved in polynomial time for graphs with maximum degree 3, but is APX-hard for graphs with maximum degree 4. For g is an element of {4, 5}, we show that both problems allow polynomial time algorithms for instances with Maximum degree 3, but are APX-hard for instances with maximum degree 4. For each g >= 6, both problems are APX-hard already for graphs with maximum degree 3. (C) 2009 Elsevier B.V. All rights reserved.
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