Given a graph G = ( V , E ) , a vertex u E V ve-dominates all edges incident to any vertex in the closed neighborhood N[u]. A subset D c V is a vertex-edge dominating set if, for each edge e E E , there exists a verte...
详细信息
Given a graph G = ( V , E ) , a vertex u E V ve-dominates all edges incident to any vertex in the closed neighborhood N[u]. A subset D c V is a vertex-edge dominating set if, for each edge e E E , there exists a vertex u E D such that u ve-dominates e . The objective of the ve-domination problem is to find a minimum cardinality ve-dominating set in G . In this paper, we present a linear time algorithm to find a minimum cardinality ve-dominating set for convex bipartite graphs, which is a superclass of bipartite permutation graphs and a subclass of bipartite graphs, where the ve-domination problem is solvable in lineartime and NP-complete, respectively. We also establish the relationship y ve = i v e for convex bipartite graphs. Our approach leverages a chain decomposition of convex bipartite graphs, allowing for efficient identification of minimum ve-dominating sets and extending algorithmic insights into ve-domination for specific structured graph classes.
It remains an open problem to find the optimal configuration of phase shifts under the discrete constraint for intelligent reflecting surface (IRS) in polynomial time. The above problem is widely believed to be diffic...
详细信息
It remains an open problem to find the optimal configuration of phase shifts under the discrete constraint for intelligent reflecting surface (IRS) in polynomial time. The above problem is widely believed to be difficult because it is not linked to any known combinatorial problems that can be solved efficiently. The branch-and-bound algorithms and the approximation algorithms constitute the best results in this area. Nevertheless, this letter shows that the global optimum can actually be reached in lineartime on average in terms of the number of reflective elements (REs) of IRS. The main idea is to geometrically interpret the discrete beamforming problem as choosing the optimal point on the unit circle. Although the number of possible combinations of phase shifts grows exponentially with the number of REs, it turns out that there are only a linear number of circular arcs that possibly contain the optimal point. Furthermore, the proposed algorithm can be viewed as a novel approach to a special case of the discrete quadratic program (QP).
We study the problem of finding a set of p connected vertices in a block graph to minimize the convex combination of the median and the center objective functions. This problem is called the connected p-centdian probl...
详细信息
We study the problem of finding a set of p connected vertices in a block graph to minimize the convex combination of the median and the center objective functions. This problem is called the connected p-centdian problem on block graphs. In the scope of this paper, we always focus on unweighted block graphs. For block graphs with two different edge lengths, the problem is NP-complete. For block graphs with uniform edge lengths, we focus on a special case of the connected p-centdian problem, namely where the median and the center functions receive equal weight. Concerning this specific problem, we consider a lexicographic order based on certain labels of the vertices and prove that there exists a connected p-centdian that contains a predetermined 1-centdian on the underlying graph. Applying this result, we develop a linear time algorithm for the problem. Finally, the problem under the general convex combination of the median and the center functions is also discussed. (c) 2022 Elsevier B.V. All rights reserved.
Motivated by the design of cost-efficient communication networks, the problem about Maximum Internal Spanning Tree that arises in a connected graph, is proposed to find a spanning tree with the maximum number of inter...
详细信息
Motivated by the design of cost-efficient communication networks, the problem about Maximum Internal Spanning Tree that arises in a connected graph, is proposed to find a spanning tree with the maximum number of internal vertices. In 2018, Xingfu Li et al. presented a polynomial algorithm to find a maximum internal spanning tree in a connected interval graph. Based on the structure of normal orderings on interval graphs, we present a simple linear time algorithm that solve the problem when restricted to connected interval graphs in this paper. The proof provides additional insight about the linear time algorithm on interval graphs.(c) 2022 Elsevier B.V. All rights reserved.
Influence maximization is the problem of finding k seed nodes in a given network as information sources so that the influence cascade can be maximized. To solve this problem both efficiently and effectively, in this p...
详细信息
ISBN:
(纸本)9783319701394;9783319701387
Influence maximization is the problem of finding k seed nodes in a given network as information sources so that the influence cascade can be maximized. To solve this problem both efficiently and effectively, in this paper we propose LAIM: a linear time algorithm for influence maximization in large-scale social networks. Our LAIM algorithm consists of two parts: (1) influence computation;and (2) seed nodes selection. The first part approximates the influence of any node using its local influence, which can be efficiently computed with an iterative algorithm. The second part selects seed nodes in a greedy manner based on the results of the first part. We theoretically prove that the time and space complexities of our algorithm are proportional to the network size. Experimental results on six real-world datasets show that our approach significantly outperforms other state-of-the-art algorithms in terms of influence spread, running time and memory usage.
An undirected graph G = (V, E) has metric dimension at most k if there is a vertex set U subset of V such that vertical bar U vertical bar <= k and for all u, v is an element of V, u not equal v, there is a vertex ...
详细信息
An undirected graph G = (V, E) has metric dimension at most k if there is a vertex set U subset of V such that vertical bar U vertical bar <= k and for all u, v is an element of V, u not equal v, there is a vertex w is an element of U such that d(G)(w, u) not equal d(G)(w, v), where d(G)(u, v) is the distance (the length of a shortest path in an unweighted graph) between u and v. The metric dimension of G is the smallest integer k such that G has metric dimension at most k. A cactus block graph is an undirected graph whose biconnected components are either cycles or complete graphs. We present a linear time algorithm for computing the metric dimension of cactus block graphs. (C) 2016 Elsevier B.V. All rights reserved.
The Hitchcock transportation problem is a special case of the minimum cost flow problem where the graph is bipartite and capacities are infinite. If we let m denote the size of the larger and n the size of the smaller...
详细信息
The Hitchcock transportation problem is a special case of the minimum cost flow problem where the graph is bipartite and capacities are infinite. If we let m denote the size of the larger and n the size of the smaller side of the bipartition, we call the Hitchcock transportation problem unbalanced if m is much larger than n. The unbalanced case arises in various applications, motivating the search for algorithms whose running time dependence on m is as small as possible. In this work, we give an algorithm with running time , which is the fastest known algorithm whose running time grows linearly in m. Moreover, we compare running times of algorithms for the Hitchcock transportation problem and the minimum cost flow problem and point out the fastest algorithms for particular relations of m and n, where m and n denote the number of edges and vertices in the context of the minimum cost flow problem. (c) 2015 Wiley Periodicals, Inc. NETWORKS, Vol. 67(2), 170-182 2016
A well-known result about satisfiability theory is that the 2-SAT problem can be solved in lineartime, despite the N P-hardness of the 3-SAT problem. In the quantum 2-SAT problem, we are given a family of 2-qubit pro...
详细信息
A well-known result about satisfiability theory is that the 2-SAT problem can be solved in lineartime, despite the N P-hardness of the 3-SAT problem. In the quantum 2-SAT problem, we are given a family of 2-qubit projectors pi(ij) on a system of n qubits, and the task is to decide whether the Hamiltonian H = Sigma pi(ij) has a 0-eigenvalue, or all eigenvalues are greater than 1/n(alpha) for some alpha = O(1). The problem is not only a natural extension of the classical 2-SAT problem to the quantum case, but is also equivalent to the problem of finding a ground state of 2-local frustration-free Hamiltonians of spin 1/2, a well-studied model believed to capture certain key properties in modern condensed matter physics. Bravyi has shown that the quantum 2-SAT problem has a deterministic algorithm of complexity O(n(4)) in the algebraic model of computation where every arithmetic operation on complex numbers can be performed in unit time, and n is the number of variables. In this paper we give a deterministic algorithm in the algebraic model with running time O(n + m), where m is the number of local projectors, therefore achieving the best possible complexity in that model. We also show that if in the input every number has a constant size representation then the bit complexity of our algorithm is O((n+m)M(n)), where M(n) denotes the complexity of multiplying two n-bit integers.
A maximal clique of G is a clique not properly contained in any other clique. A k-clique-coloring of a graph G is an assignment of k colors to the vertices of G such that no maximal clique with at least two vertices i...
详细信息
A maximal clique of G is a clique not properly contained in any other clique. A k-clique-coloring of a graph G is an assignment of k colors to the vertices of G such that no maximal clique with at least two vertices is monochromatic. The smallest integer k admitting a k-clique-coloring of G is called clique-coloring number of G. Cerioli and Korenchendler (Electron Notes Discret Math 35:287-292, 2009) showed that there is a polynomial-timealgorithm to solve the clique-coloring problem in circular-arc graphs and asked whether there exists a linear-timealgorithm to find an optimal clique-coloring in circular-arc graphs or not. In this paper we present a linear-timealgorithm of the optimal clique-coloring in circular-arc graphs.
Given a graph G=(V,E) and a positive integer p≤|E|. The Line Subgraph Problem is: Is there a subset E'?E such that |E'|≥p and H=(V,E) is a line graph. In this paper, we design a linear time algorithm to solv...
详细信息
ISBN:
(纸本)9781510833890
Given a graph G=(V,E) and a positive integer p≤|E|. The Line Subgraph Problem is: Is there a subset E'?E such that |E'|≥p and H=(V,E) is a line graph. In this paper, we design a linear time algorithm to solve the line subgraph problem for Halin graphs. The algorithm is optimal.
暂无评论