• J. Comb. Optim. (IF 0.843) Pub Date : 2020-08-01
Lu Han, Dachuan Xu, Yicheng Xu, Dongmei Zhang

In this paper, we consider the $$\tau$$-relaxed soft capacitated facility location problem ($$\tau$$-relaxed SCFLP), which extends several well-known facility location problems like the squared metric soft capacitated facility location problem (SMSCFLP), soft capacitated facility location problem (SCFLP), squared metric facility location problem and uncapacitated facility location problem. In the

更新日期：2020-08-01
• J. Comb. Optim. (IF 0.843) Pub Date : 2020-07-28
Wenguo Yang, Shengminjie Chen, Suixiang Gao, Ruidong Yan

In a social network, the propagation of information has sparked intense research. Influence Maximization (IM) is a well-studied problem that asks for k nodes to influence the largest users in the social network. However IM is submodular at the most time. In recent years, many non-submodular problems have been proposed and researchers give a lot of algorithms to solve them. In this paper, we propose

更新日期：2020-07-29
• J. Comb. Optim. (IF 0.843) Pub Date : 2020-07-25
Yong Chen, Guohui Lin, Tian Liu, Taibo Luo, Bing Su, Yao Xu, Peng Zhang

The maximum duo-preservation string mapping (Max-Duo) problem is the complement of the well studied minimum common string partition problem, both of which have applications in many fields including text compression and bioinformatics. k-Max-Duo is the restricted version of Max-Duo, where every letter of the alphabet occurs at most k times in each of the strings, which is readily reduced into the well

更新日期：2020-07-25
• J. Comb. Optim. (IF 0.843) Pub Date : 2020-07-22
Irene Sciriha, Xandru Mifsud, James L. Borg

The core vertex set of a graph is an invariant of the graph. It consists of those vertices associated with the non-zero entries of the nullspace vectors of a $$\{0,1\}$$-adjacency matrix. The remaining vertices of the graph form the core-forbidden vertex set. For graphs with independent core vertices, such as bipartite minimal configurations and trees, the nullspace induces a well defined three part

更新日期：2020-07-22
• J. Comb. Optim. (IF 0.843) Pub Date : 2020-07-20
Oleg Duginov

We introduce two problems related to finding in a weighted complete bipartite graph a special matching such that the maximum weight of its some subsets is minimal. We discuss their applications and show the strong NP-hardness of both problems. We show that one problem cannot be approximated in polynomial time within a factor of less than 2 and another problem cannot be approximated in polynomial time

更新日期：2020-07-21
• J. Comb. Optim. (IF 0.843) Pub Date : 2020-07-17
Zhenning Zhang, Bin Liu, Yishui Wang, Dachuan Xu, Dongmei Zhang

Submodular optimization has been well studied in combinatorial optimization. However, there are few works considering about non-submodular optimization problems which also have many applications, such as experimental design, some optimization problems in social networks, etc. In this paper, we consider the maximization of non-submodular function under a knapsack constraint, and explore the performance

更新日期：2020-07-17
• J. Comb. Optim. (IF 0.843) Pub Date : 2020-07-16
Zhuo Pan, Xianyue Li, Shou-Jun Xu

For a connected graph $$G = (V, E)$$, a subset F of E is an edge dominating set (resp. a total edge dominating set) if every edge in $$E-F$$ (resp. in E) is adjacent to at least one edge in F, the minimum cardinality of an edge dominating set (resp. a total edge dominating set) of G is the edge domination number (resp. total edge domination number) of G, denoted by $$\gamma '(G)$$ (resp. $$\gamma '_t(G)$$)

更新日期：2020-07-17
• J. Comb. Optim. (IF 0.843) Pub Date : 2020-07-16
Zhichao Geng, Jiayu Liu

We investigate the scheduling problem on a single bounded parallel-batch machine where jobs belong to two non-disjoint agents (called agent A and agent B) and are of equal length but different size. Each job’s size can be arbitrarily split into two parts and processed in the consecutive batches. It is permitted to process the jobs from different agents in a common batch. We show that it is unary NP-hard

更新日期：2020-07-17
• J. Comb. Optim. (IF 0.843) Pub Date : 2020-07-16
Hui Zhang, Kai Luo, Guanqun Ni

In this paper, from the perspective of game theory, we study the impact of price subsidy and fairness concern on the pricing strategies and benefits of members in the take-away industry. In the single-channel supply chain, we build a Stackelberg game model between the take-away platform and the restaurant for the online take-away business. By comparing and analyzing the product pricing and revenue

更新日期：2020-07-16
• J. Comb. Optim. (IF 0.843) Pub Date : 2020-07-13
Qi Chen, Qi Xu

The original design manufacturing (ODM) strategy has become popular in the fashion supply chain field. We consider apparel’s fashion level and advertising effort as important influential factors on goodwill, and present a differential game involving a fashion brand and a supplier. The supplier controls the design improvement effort applied to the apparel and sells it to end consumers through the fashion

更新日期：2020-07-13
• J. Comb. Optim. (IF 0.843) Pub Date : 2020-07-07
Anil Maheshwari, Arash Nouri, Jörg-Rüdiger Sack

We present an optimal algorithm for determining a time-minimal rectilinear path among transient rectilinear obstacles. An obstacle is transient if it exists only for a specific time interval, i.e., it appears and then disappears at specific times. Given a point robot moving with bounded speed among non-intersecting transient rectilinear obstacles and a pair of points (s, d), we determine a time-minimal

更新日期：2020-07-07
• J. Comb. Optim. (IF 0.843) Pub Date : 2020-07-06
Shuangyao Zhao, Qiang Zhang, Zhanglin Peng, Xiaonong Lu

Owing to the rapid proliferation of service technologies in cross-enterprise manufacturing collaborations, manufacturing service composition (MSC) has attracted much attention from both academia and industries. However, the existing service composition is often constructed by the combination of off-line and on-line services, quality of service (QoS) attributes are not appropriate for satisfying the

更新日期：2020-07-07
• J. Comb. Optim. (IF 0.843) Pub Date : 2020-07-03
Ming Liu, Rongfan Liu, E Zhang, Chengbin Chu

Currently, a huge amount of cargo is transported via containers by liner shipping companies. Under stochastic demand, repacking operations and carbon reduction, which may lead to an increase in effectiveness and environmental improvement, have been rarely considered in previous literature. In this paper, we investigate a container transshipment route scheduling problem with repacking operations under

更新日期：2020-07-03
• J. Comb. Optim. (IF 0.843) Pub Date : 2020-06-29
João Vinicius C. Thompson, Loana T. Nogueira, Fábio Protti, Raquel S. F. Bravo, Mitre C. Dourado, Uéverton S. Souza

In this work we deal with the so-called path convexities, defined over special collections of paths. For example, the collection of the shortest paths in a graph is associated with the well-known geodesic convexity, while the collection of the induced paths is associated with the monophonic convexity; and there are many other examples. Besides reviewing the path convexities in the literature, we propose

更新日期：2020-06-29
• J. Comb. Optim. (IF 0.843) Pub Date : 2020-06-28
B. S. Panda, Arti Pandey, Juhi Chaudhary, Piyush Dane, Manav Kashyap

A subset $$M\subseteq E$$ of edges of a graph $$G=(V,E)$$ is called a matching in G if no two edges in M share a common vertex. A matching M in G is called an induced matching if G[M], the subgraph of G induced by M, is the same as G[S], the subgraph of G induced by $$S=\{v \in V |$$v is incident on an edge of $$M\}$$. The Maximum Induced Matching problem is to find an induced matching of maximum cardinality

更新日期：2020-06-28
• J. Comb. Optim. (IF 0.843) Pub Date : 2020-06-27
Haiyan Yu, Xianwei Luo, Tengyu Wu

The online pickup and delivery problem is motivated by the takeaway order delivery on crowdsourcing delivery platform, which is a newly emerged online to offline business model based on sharing economy. Considering the features of crowdsourcing delivery, an online pickup and delivery problem with constrained capacity is proposed, whose objective is to route a delivery man with constrained capacity

更新日期：2020-06-27
• J. Comb. Optim. (IF 0.843) Pub Date : 2020-06-26
P. Dankelmann, F. J. Osaye

Let G be a connected finite graph with vertex set V(G). The eccentricity e(v) of a vertex v is the distance from v to a vertex farthest from v. The average eccentricity of G is defined as $$\frac{1}{|V(G)|}\sum _{v \in V(G)}e(v)$$. We show that the average eccentricity of a connected graph of order n, minimum degree $$\delta$$ and maximum degree $$\Delta$$ does not exceed $$\frac{9}{4} \frac{n-\Delta 更新日期：2020-06-26 • J. Comb. Optim. (IF 0.843) Pub Date : 2020-06-25 Chun-lin Xin, Shuo Liang, Feng-wu Shen With urban development, many small urban areas are being integrated into large ones, which leads to redundancy of domestic waste disposal facilities. How to optimize these facilities is a major problem of urban administrative departments. In this study, we consider three strategies to deal with this problem, which are redundant deletion, garbage bin redistribution, and system reconstruction, through 更新日期：2020-06-26 • J. Comb. Optim. (IF 0.843) Pub Date : 2020-06-25 Jing Wang, Liying Kang, Erfang Shan For a connected hypergraph H with \(rank(H)=r$$ , let $$\mathcal {D}(H)$$ and $$\mathcal {A}(H)$$ be the diagonal tensor of degrees and the adjacency tensor of H, respectively. For $$0 \le \alpha < 1$$, the $$\alpha$$-spectral radius $$\rho _{\alpha }(H)$$ of H is defined as $$\rho _{\alpha }(H)=\max \{x^{T}(\mathcal {A}_{\alpha }x)|x \in \mathbf {R}_{+}^{n},\Vert x\Vert _{r}=1\}$$, where $$\mathcal 更新日期：2020-06-25 • J. Comb. Optim. (IF 0.843) Pub Date : 2020-06-24 Sai Ji, Dachuan Xu, Min Li, Yishui Wang Correlation clustering problem is a clustering problem which has many applications such as protein interaction networks, cross-lingual link detection, communication networks, and social computing. In this paper, we introduce two variants of correlation clustering problem: correlation clustering problem on uncertain graphs and correlation clustering problem with non-uniform hard constrained cluster 更新日期：2020-06-25 • J. Comb. Optim. (IF 0.843) Pub Date : 2020-06-21 Hazhar Rahmani, Jason M. O’Kane Combinatorial filters, which take the form of labelled transition graphs, are a general representation for filtering and inference tasks in robotics. They are of particular interest in contexts where the objective is to minimize the computational resources needed to execute the filter. One specific problem is called the filter minimization (FM) problem, in which the goal is to find, for a given original 更新日期：2020-06-22 • J. Comb. Optim. (IF 0.843) Pub Date : 2020-06-20 Jian Wang, Yin Wang, Mingzhu Yu To achieve quick response in the disaster, this paper addresses the issue of ambulance location and allocation, as well as the location problem of temporary medical centers. Considering budget and capacity limitations, a multi-period mixed integer programming model is proposed and two hybrid heuristic algorithms are designed to solve this complex problem. The proposed model and algorithm are further 更新日期：2020-06-22 • J. Comb. Optim. (IF 0.843) Pub Date : 2020-06-20 Norelhouda Sekkal, Fayçal Belkaid Production systems are subject to machine deterioration and resource consumption constraints. The deterioration increases the processing time which leads to an increase in resource consumption. In this study, we investigate and model the behavior of a parallel machine scheduling problem with respect to the processing time. The machine is subject to deterioration and includes two resource consumption 更新日期：2020-06-22 • J. Comb. Optim. (IF 0.843) Pub Date : 2020-06-17 Mingyu Xiao, Jianan Zhang, Weibo Lin The traveling purchaser problem (TPP), a generalization of the traveling salesman problem, is to determine a tour of suppliers and purchase needed products from suppliers while minimizing the traveling and purchasing cost. This problem finds applications in the routing and scheduling contexts and its variants with different constraints have been widely studied. Motivated by the phenomenon that most 更新日期：2020-06-18 • J. Comb. Optim. (IF 0.843) Pub Date : 2020-06-15 Xuqing Bai, Hong Chang, Xueliang Li A set B of vertices in a graph G is called a k-limited packing if for each vertex v of G, its closed neighbourhood has at most k vertices in B. The k-limited packing number of a graph G, denoted by \(L_k(G)$$, is the largest number of vertices in a k-limited packing in G. The concept of the k-limited packing of a graph was introduced by Gallant et al., which is a generalization of the well-known packing

更新日期：2020-06-18
• J. Comb. Optim. (IF 0.843) Pub Date : 2020-06-13
Masoumeh Zojaji, Mohammad Reza Mollakhalili Meybodi, Kamal Mirzaie

Generalized minimum spanning tree problem, which has several real-world applications like telecommunication network designing, is related to combinatorial optimization problems. This problem belongs to the NP-hard class and is a minimum tree on a clustered graph spanning one node from each cluster. Although exact and metaheuristic algorithms have been applied to solve the problems successfully, obtaining

更新日期：2020-06-13
• J. Comb. Optim. (IF 0.843) Pub Date : 2020-06-12

Due to data compression or low resolution, nearby vertices and edges of a graph drawn in the plane may be bundled to a common node or arc. We model such a “compromised” drawing by a piecewise linear map $$\varphi :G\rightarrow {\mathbb {R}}^2$$. We wish to perturb $$\varphi$$ by an arbitrarily small $$\varepsilon >0$$ into a proper drawing (in which the vertices are distinct points, any two edges

更新日期：2020-06-12
• J. Comb. Optim. (IF 0.843) Pub Date : 2020-06-11
Wenqiang Dai, Meng Zheng, Xu Chen, Zhuolin Yang

Traditional economic ordering model for deteriorating items assume the procurer have full information about the procurement price. In this paper, we study an online economic ordering problem for constant deteriorating rate items with limited price information under relative performance criterion of the competitive ratio (CR). We provide a simply procurement strategy as well as the optimal ordering

更新日期：2020-06-11
• J. Comb. Optim. (IF 0.843) Pub Date : 2020-06-11
Vittorio Bilò, Francesco Cellinese, Giovanna Melideo, Gianpiero Monaco

We consider selfish colorful bin packing games in which a set of items, each one controlled by a selfish player, are to be packed into a minimum number of unit capacity bins. Each item has one of $$m\ge 2$$ colors and no items of the same color may be adjacent in a bin. All bins have the same unitary cost which is shared among the items it contains, so that players are interested in selecting a bin

更新日期：2020-06-11
• J. Comb. Optim. (IF 0.843) Pub Date : 2020-06-11
Pan Li, Qiang Hua, Zhijun Hu, Hing-Fung Ting, Yong Zhang

We consider the market mechanism to sell two types of products, A and B, to a set of buyers $$I=\{1, 2, \ldots , n\}$$. The amounts of products are $$m_A$$ and $$m_B$$ respectively. Each buyer i has his information including the budget, the preference and the utility function. On collecting the information from all buyers, the market maker determines the price of each product and allocates some amount

更新日期：2020-06-11
• J. Comb. Optim. (IF 0.843) Pub Date : 2020-06-10
Cong Chen, Yinfeng Xu

This paper studies the favorite machine model, where each machine has different speed for different types of jobs. The model is a natural generalization of the two related machines model and captures the features of some real life problems, such as the CPU–GPU task scheduling, the two products scheduling and the cloud computing task scheduling. We are interested in the game-theoretic version of the

更新日期：2020-06-10
• J. Comb. Optim. (IF 0.843) Pub Date : 2020-06-09
Deshi Ye, Feng Xie, Guochuan Zhang

In this paper, we study a mechanism design for the bin packing problem, which can model a reversed auction on cloud computing. A cloud computing platform has a set of jobs and would like to rent VM instances to process these jobs from cloud providers. In the auction model, each cloud provider (agent) who owns VM instances will submit a bid on the costs for using such VM instances. The mechanism determines

更新日期：2020-06-09
• J. Comb. Optim. (IF 0.843) Pub Date : 2020-06-08
Yongjian Yang, Guangqiang Yin, Chunyu Wang, Yunqiang Yin

This paper addresses a two-agent scheduling problem with due date assignment under multitasking environment, in which the due dates of the jobs from the first agent are decision variables to be determined using the unrestricted (usually referred to as DIF) due date assignment method. Each agent requests the processing of its own set of jobs on a machine and wishes to minimize a certain scheduling criterion

更新日期：2020-06-08
• J. Comb. Optim. (IF 0.843) Pub Date : 2020-06-06
Pawan Aurora, Shashank K. Mehta

Aurora and Mehta (J Comb Optim 36(3):965–1006, 2018) show that two graphs $$G_1,G_2$$, on n vertices each, are isomorphic if and only if the feasible region of a certain linear program, LP-GI, intersects with the Quadratic Assignment Problem (QAP)-polytope in $${\mathbb {R}}^{(n^4+n^2)/2}$$. The linear program LP-GI in Aurora and Mehta (J Comb Optim 36(3):965–1006, 2018) is obtained by relaxing an

更新日期：2020-06-06
• J. Comb. Optim. (IF 0.843) Pub Date : 2020-06-05
Zhuo Pan, Yu Yang, Xianyue Li, Shou-Jun Xu

For a graph $$G = (V, E)$$ with vertex set V and edge set E, a subset F of E is called an edge dominating set (resp. a total edge dominating set) if every edge in $$E\backslash F$$ (resp. in E) is adjacent to at least one edge in F, the minimum cardinality of an edge dominating set (resp. a total edge dominating set) of G is the edge domination number (resp. total edge domination number) of G, denoted

更新日期：2020-06-05
• J. Comb. Optim. (IF 0.843) Pub Date : 2020-06-05
J. Amjadi, R. Khoeilar, M. Chellali, Z. Shao

A Roman dominating function (RDF) of a graph G is a labeling $$f:V(G)\longrightarrow \{0,1,2\}$$ such that every vertex with label 0 has a neighbor with label 2. The weight of an RDF is the sum of its functions values over all vertices, and the Roman domination number of G is the minimum weight of an RDF of G. The Roman domination subdivision number $$\mathrm {sd}_{\gamma _{R}}(G)$$ is the minimum

更新日期：2020-06-05
• J. Comb. Optim. (IF 0.843) Pub Date : 2020-06-05
Yinling Wang, Yan Lan, Xin Chen, Xin Han, Yong Piao

This paper focuses on the scheduling problem on two parallel machines with delivery coordination. In particular, given a set of n jobs, we aim to find a schedule with a minimal makespan such that all jobs are first executed on two parallel machines then delivered at the destination with a transporter. This problem is known to be NP-hard Chang and Lee (Eur J Oper Res 158(2):470–487, 2004), cannot be

更新日期：2020-06-05
• J. Comb. Optim. (IF 0.843) Pub Date : 2020-06-05
Tanima Chatterjee, Bhaskar DasGupta, Laura Palmieri, Zainab Al-Qurashi, Anastasios Sidiropoulos

Partisan gerrymandering is a major cause for voter disenfranchisement in United States. However, convincing US courts to adopt specific measures to quantify gerrymandering has been of limited success to date. Recently, Stephanopoulos and McGhee in several papers introduced a new measure of partisan gerrymandering via the so-called “efficiency gap” that computes the absolute difference of wasted votes

更新日期：2020-06-05
• J. Comb. Optim. (IF 0.843) Pub Date : 2020-06-04
Zeynep Adak, Mahmure Övül Arıoğlu Akan, Serol Bulkan

Multi-processor open shop (MPOS) is a combination of the classical open shop and parallel shop environments. Although there exist wide application areas of this shop environment in both production and service facilities, the research in the field is still limited. In this paper, we provided a detailed review of the research on MPOS problem. With this survey, we aimed to provide a helpful guide to those

更新日期：2020-06-04
• J. Comb. Optim. (IF 0.843) Pub Date : 2020-06-02
Diego P. Rubert, Eloi Araujo, Marco A. Stefanes, Jens Stoye, Fábio V. Martinez

The analysis of biological networks allows the understanding of many biological processes, including the structure, function, interaction and evolutionary relationships of their components. One of the most important concepts in biological network analysis is that of network motifs, which are patterns of interconnections that occur in a given network at a frequency higher than expected in a random network

更新日期：2020-06-02
• J. Comb. Optim. (IF 0.843) Pub Date : 2020-06-02
Prosenjit Bose, Valentin Gledel, Claire Pennarun, Sander Verdonschot

The concept of power domination emerged from the problem of monitoring electrical systems. Given a graph G and a set $$S \subseteq V(G)$$, a set M of monitored vertices is built as follows: at first, M contains only the vertices of S and their direct neighbors, and then each time a vertex in M has exactly one neighbor not in M, this neighbor is added to M. The power domination number of a graph G is

更新日期：2020-06-02
• J. Comb. Optim. (IF 0.843) Pub Date : 2020-06-02
Brad D. Woods, Abraham P. Punnen

The quadratic travelling salesman problem (QTSP) is to find a least-cost Hamiltonian cycle in an edge-weighted graph, where costs are defined on all pairs of edges such that each edge in the pair is contained in the Hamiltonian cycle. This is a more general version than the one that appears in the literature as the QTSP, denoted here as the adjacent quadratic TSP, which only considers costs for pairs

更新日期：2020-06-02
• J. Comb. Optim. (IF 0.843) Pub Date : 2020-06-01
Hakan Kutucu, Arif Gursoy, Mehmet Kurt, Urfat Nuriyev

In order to reduce costs in the telecommunication sector, many mathematical models have been developed. Over time, these models either fall out out of use or are revised according to new technological developments. The Bandpass Problem (BP) is an optimization problem introduced in 2004 to reduce hardware costs in communication networks. However, over time, technological advances in fiber-optic networks

更新日期：2020-06-01
• J. Comb. Optim. (IF 0.843) Pub Date : 2020-05-30
E. Zhang, Feng Chu, Shijin Wang, Ming Liu, Yang Sui

This paper studies the vessel fleet deployment problem for liner shipping under uncertain shipment demands. The aim is to minimize the sum of vessel chartering cost and route operating cost, while controlling the risk of shipment demand overflow, i.e., the risk of demand exceeding the shipping capacity. We use moment knowledge to construct an ambiguous set to portray the unknown probability distributions

更新日期：2020-05-30
• J. Comb. Optim. (IF 0.843) Pub Date : 2020-05-28
Fernando A. Morales, Jairo A. Martínez

We introduce and asses several Divide-and-Conquer heuristic strategies, aimed at solving large instances of the 0–1 Minimization Knapsack Problem. The method subdivides a large problem in two smaller ones (or recursive iterations of the same procedure), in order to lower down the global computational complexity of the original problem, at the expense of a moderate loss of quality in the solution. Theoretical

更新日期：2020-05-28
• J. Comb. Optim. (IF 0.843) Pub Date : 2020-05-27
Long Zhang, Yuzhong Zhang, Qingguo Bai

This paper studies single machine scheduling with batch deliveries, where a common due window for all jobs has to be determined, not given in advance. The objective is to minimize the overall cost for the process and delivery. Concretely, it includes the penalty of a job being early or tardy, the cost for holding and delivering a job, and the cost incurred by a late starting or a long duration of the

更新日期：2020-05-27
• J. Comb. Optim. (IF 0.843) Pub Date : 2020-05-25
Tengyu Wu, Lin He, Haiyan Yu

Considering that the time of meeting the demands is very important for emergency vehicle and emergency vehicle can’t reject any request, we introduce a more realistic cost form into online traveling salesman problem(OL-TSP). When a new request arrives, if the salesman can’t serve the request immediately, per-unit-time cost will be generated. The goal is to minimize server’s total costs(travel makespan

更新日期：2020-05-25
• J. Comb. Optim. (IF 0.843) Pub Date : 2020-05-24
Chenlan Wang, Xuan Vinh Doan, Bo Chen

In this paper, we present a new model of congestion games with finite and random number of players, and an analytical method to compute the random path and link flows. We study the equilibrium condition, reformulate it as an equivalent variational inequality problem, and establish the existence and non-uniqueness of the equilibria. We also upper bound the price of anarchy with affine cost functions

更新日期：2020-05-24
• J. Comb. Optim. (IF 0.843) Pub Date : 2020-05-17
Yubai Zhang, Zhao Zhang, Zhaohui Liu

This paper studies the price of fairness in a two-agent single machine scheduling game. In this game, two agents compete to perform their jobs on a common single machine. Both of the two agents want to minimize their own total completion time. One of them has exactly two jobs. All processing times are positive. We show that all Kalai-Smorodinsky fair schedules can be found in linear time, and its price

更新日期：2020-05-17
• J. Comb. Optim. (IF 0.843) Pub Date : 2020-05-15
Lily Chen, Shumei Chen, Ren Zhao, Xiangqian Zhou

The edge weight of a graph G is defined to be $$\max \{d_G(u) + d_G(v): uv \in E(G)\}$$. The strong chromatic index of a graph is the minimum value of k such that the edge set of G can be partitioned into k induced matchings. In this article, we prove that the strong chromatic index of a graph with edge weight eight is at most 21.

更新日期：2020-05-15
• J. Comb. Optim. (IF 0.843) Pub Date : 2020-05-08
Abbas Salehi, Behrooz Masoumi

In the field of social networks, the Influence Maximization Problem (IMP) is one of the most well-known issues that have attracted many researchers in recent years. Influence Maximization (IM) means trying to find the best subset of K nodes that maximizes the number of nodes influenced by this subset. The IM is an NP-hard problem that plays an important role in viral marketing and dissemination of

更新日期：2020-05-08
• J. Comb. Optim. (IF 0.843) Pub Date : 2020-05-05
Pei Yao, Longkun Guo

For a given undirected graph with each edge associated with a weight and a length, the constrained minimum spanning tree (CMST) problem aims to compute a minimum weight spanning tree with total length bounded by a given fixed integer $$L\in {\mathbb {Z}}^{+}$$. In the paper, we first present an exact algorithm with a runtime $$O(mn^{2})$$ for CMST when the edge length is restricted to 0 and 1 based

更新日期：2020-05-05
• J. Comb. Optim. (IF 0.843) Pub Date : 2020-05-02
Rahul Swamy, Timothy Murray

This paper studies the computation of pure Nash equilibrium (PNE) in network utility-sharing and discretized Hotelling–Downs games, and the interplay between these classes of games. First, we introduce and study a variant of network utility-sharing games with additional player-specific non-shareable costs (NUSG+), which is shown to possess a PNE. We extend polynomial-time PNE computation results to

更新日期：2020-05-02
• J. Comb. Optim. (IF 0.843) Pub Date : 2020-04-29
Qin Wang, Tianyu Yang, Longshu Wu

In this paper, we study the general restricted inverse assignment problems, in which we can only change the costs of some specific edges of an assignment problem as less as possible, so that a given assignment becomes the optimal one. Under $$l_1$$ norm, we formulate this problem as a linear programming. Then we mainly consider two cases. For the case when the specific edges are only belong to the

更新日期：2020-04-29
• J. Comb. Optim. (IF 0.843) Pub Date : 2020-04-25
Changhong Lu, Qingjie Ye, Chengru Zhu

Let G be a simple graph, where each vertex has a nonnegative weight. A vertex subset S of G is a doubly resolving set (DRS) of G if for every pair of vertices u, v in G, there exist $$x,y\in S$$ such that $$d(x,u)-d(x,v)\ne d(y,u)-d(y,v)$$. The minimum weighted doubly resolving set (MWDRS) problem is finding a doubly resolving set with minimum total weight. We establish a linear time algorithm for

更新日期：2020-04-25
• J. Comb. Optim. (IF 0.843) Pub Date : 2020-04-25

Steinberg-type graphs, those planar graphs containing no 4-cycles or 5-cycles, became well known with the 1976 Steinberg Conjecture which stated that such graphs are properly 3-colorable. Recently, Steinberg’s Conjecture was demonstrated to be false (Cohen-Addad et al. in J Combin Theory Ser B 122: 452–456, 2016). However, Steinberg-type graphs are (3, 0, 0)-defective colorable (Hill et al. in Discrete

更新日期：2020-04-25
• J. Comb. Optim. (IF 0.843) Pub Date : 2020-04-25
Kelly B. Yancey, Matthew P. Yancey

In this paper we are interested in finding communities with bipartite structure. A bipartite community is a pair of disjoint vertex sets S, $$S'$$ such that the number of edges with one endpoint in S and the other endpoint in $$S'$$ is “significantly more than expected.” This additional structure is natural to some applications of community detection. In fact, using other terminology, they have already

更新日期：2020-04-25
• J. Comb. Optim. (IF 0.843) Pub Date : 2020-04-24
Ji Tian, Yan Zhou, Ruyan Fu

We consider a semi-online scheduling problem on a single machine with an unexpected breakdown period. In the problem, each job has a processing time and a subsequent delivery time. All these data are known in the beginning. The scheduler has to determine a sequence S of these jobs for processing. After S is given, a machine unavailability period may occur where its starting time and length are not

更新日期：2020-04-24
• J. Comb. Optim. (IF 0.843) Pub Date : 2020-04-22
Thi Thanh Sang Nguyen, Pham Minh Thu Do

Book classification is very popular in digital libraries. Book rating prediction is crucial to improve the care of readers. The commonly used techniques are decision tree, Naïve Bayes (NB), neural networks, etc. Moreover, mining book data depends on feature selection, data pre-processing, and data preparation. This paper proposes the solutions of knowledge representation optimization as well as feature

更新日期：2020-04-22
• J. Comb. Optim. (IF 0.843) Pub Date : 2020-04-15
Sai Ji, Dachuan Xu, Longkun Guo, Min Li, Dongmei Zhang

Spherical k-means clustering as a known NP-hard variant of the k-means problem has broad applications in data mining. In contrast to k-means, it aims to partition a collection of given data distributed on a spherical surface into k sets so as to minimize the within-cluster sum of cosine dissimilarity. In the paper, we introduce spherical k-means clustering with penalties and give a \(2\max \{2,M\}(1+M)(\ln

更新日期：2020-04-15
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