We give a structural description of the class C of graphs that do not contain a cycle with a unique chord as an induced subgraph. Our main theorem states that any connected graph in C is a either in some simple basic class or has a decomposition. Basic classes are cliques, bipartite graphs with one side containing only nodes of degree two and induced subgraph of the famous Heawood or Petersen g...

In this paper, using RETINA, a real-time navigation system, as an example, we study the important design issues underlying the processing of location-dependent continuous queries, especially those requiring access to data describing the current status of a dynamic environment and possessing spatial properties. To minimize the probability of missing the arrival deadline associated with each navi...

Narrowing is a method for solving equations in the equational theories of term rewriting systems. Unification and rewriting, the central operations in narrowing, are often implemented on graph-like data structures to exploit sharing of common subexpressions. In this paper, we study the completeness of narrowing in graph-based implementations. We show that the well-known condition for the comple...

In this paper, a novel methodology is proposed to solve a cooperative multi-depot vehicle routing problem. We establish a mathematical model for multi-owner VRP in which each owner (i.e. player) manages single or multiple depots. The basic idea consists of offering an option that owners cooperatively manage the VRP to save their costs. We present cooperative game theory techniques for cost savi...

Hitchhiker organisms have been known since the earliest days of international travel, but changes in global trade mean that there are more now than ever before. They include a number of serious invasive species and are among the most difficult of quarantine problems to manage. Invasive animals transported as hitchhikers, other than plant pests, fall largely outside the international frameworks ...

This article presents a brief overview of the meaning of technical cooperation within the United Nations, underscoring the political dimension, i.e. the relationship among States. It also emphasizes the importance of health in this context, using the Americas and Brazil as a benchmark. It illustrates the new paradigm called South-South Cooperation by analyzing an experience in the health field,...

Reciprocity stabilizes cooperation from the level of microbes all the way up to humans interacting in small groups, but does reciprocity also underlie stable cooperation between larger human agglomerations, such as nation states? Famously, evolutionary models show that reciprocity could emerge as a widespread strategy for achieving international cooperation. However, existing studies have only ...

In this paper we consider S-prime graphs, that is the graphs that cannot be represented as nontrivial subgraphs of nontrivial Cartesian products of graphs. Lamprey and Barnes characterized S-prime graphs via so-called basic S-prime graphs that form a subclass of all S-prime graphs. However, the structure of basic S-prime graphs was not known very well. In this paper we prove several characteriz...

A longstanding idea in the literature on human cooperation is that cooperation should be reinforced when conditional cooperators are more likely to interact. In the context of social networks, this idea implies that cooperation should fare better in highly clustered networks such as cliques than in networks with low clustering such as random networks. To test this hypothesis, we conducted a ser...

How does natural selection lead to cooperation between competing individuals? The Prisoner's Dilemma captures the essence of this problem. Two players can either cooperate or defect. The payoff for mutual cooperation, R, is greater than the payoff for mutual defection, P. But a defector versus a cooperator receives the highest payoff, T, where as the cooperator obtains the lowest payoff, S. Hen...