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Directed Hypergraphs And Applications
, 1992
"... We deal with directed hypergraphs as a tool to model and solve some classes of problems arising in Operations Research and in Computer Science. Concepts such as connectivity, paths and cuts are defined. An extension of the main duality results to a special class of hypergraphs is presented. Algorith ..."
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Cited by 100 (5 self)
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We deal with directed hypergraphs as a tool to model and solve some classes of problems arising in Operations Research and in Computer Science. Concepts such as connectivity, paths and cuts are defined. An extension of the main duality results to a special class of hypergraphs is presented. Algorithms to perform visits of hypergraphs and to find optimal paths are studied in detail. Some applications arising in propositional logic, AndOr graphs, relational data bases and transportation analysis are presented. January 1990 Revised, October 1992 ( * ) This research has been supported in part by the "Comitato Nazionale Scienza e Tecnologia dell'Informazione", National Research Council of Italy, under Grant n.89.00208.12, and in part by research grants from the National Research Council of Canada. 1 Dipartimento di Informatica, Università di Pisa, Italy 2 Département d'Informatique et de Recherche Opérationnelle, Université de Montréal, Canada 2 INTRODUCTION Hypergraphs, a generaliz...
A Theoretical Framework For The Conception Of Agency
 International Journal of Intelligent Systems
, 1999
"... of growing importance. We propose a new machine, called agency, which is devoted to solve complex problems by means of cooperation among agents, where each agent is able to perform inferential activities. ..."
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Cited by 12 (10 self)
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of growing importance. We propose a new machine, called agency, which is devoted to solve complex problems by means of cooperation among agents, where each agent is able to perform inferential activities.
Directed Hypergraphs as a Modelling Paradigm
 RIVISTA AMASES
, 1999
"... We address a generalization of graphs, the directed hypergraphs, and show that they are a powerful tool in modelling and solving several relevant problems in many application areas. Such application areas include Linear Production Problems, Flexible Manufacturing Systems, Propositional Logic, Relat ..."
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Cited by 12 (1 self)
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We address a generalization of graphs, the directed hypergraphs, and show that they are a powerful tool in modelling and solving several relevant problems in many application areas. Such application areas include Linear Production Problems, Flexible Manufacturing Systems, Propositional Logic, Relational Databases, and Public Transportation Systems.
Perfect Graphs are Kernel Solvable
, 2000
"... In this paper we prove that perfect graphs are kernel solvable, as it was conjectured by Berge and Duchet (1983). The converse statement, i.e. that kernel solvable graphs are perfect, was also conjectured in the same paper, and is still open. In this direction we prove that it is always possible to ..."
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Cited by 2 (1 self)
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In this paper we prove that perfect graphs are kernel solvable, as it was conjectured by Berge and Duchet (1983). The converse statement, i.e. that kernel solvable graphs are perfect, was also conjectured in the same paper, and is still open. In this direction we prove that it is always possible to substitute some of the vertices of a nonperfect graph by cliques so that the resulting graph is not kernel solvable.
Stable Families of Coalitions and Normal Hypergraphs
 RUTCOR Research Report, RRR221995, Rutgers University, Mathematical Social Sciences 34
, 1997
"... The core of a game is defined as the set of outcomes acceptable for all coalitions. This is probably the simplest and most natural concept of cooperative game theory. However, the core can be empty because there are too many coalitions. Yet, some players may not like or know each other, so they cann ..."
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Cited by 1 (1 self)
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The core of a game is defined as the set of outcomes acceptable for all coalitions. This is probably the simplest and most natural concept of cooperative game theory. However, the core can be empty because there are too many coalitions. Yet, some players may not like or know each other, so they cannot form a coalition. The following generalization seems natural. Let K be a fixed family of coalitions. The Kcore is defined as the set of outcomes acceptable for all the coalitions from K. Let us call a family K gstable if the Kcore is not empty for any finite normal form game, and similarly, let K be called V stable if the Kcore is not empty for for any compact superadditive NTUgame. We prove that both V  and gstability of a family K are equivalent with the normality of K. Normal hypergraphs can be characterized by several equivalent properties, e.g. they are dual to clique hypergraphs of perfect graphs. Key words: cooperative game theory, TUgames, NTUgames, co...
NETWORK SUPPLY SYSTEMS, STABLE FAMILIES OF COALITIONS FOR SUPERADDITIVE TUGAMES AND . . .
, 2010
"... The very common question appearing in resource management is: what is the optimal way of behaviour of the agents and distribution of limited resources. Is any form of cooperation more preferable strategy then pure competition? How cooperation can be treated in the game theoretic framework: just as ..."
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The very common question appearing in resource management is: what is the optimal way of behaviour of the agents and distribution of limited resources. Is any form of cooperation more preferable strategy then pure competition? How cooperation can be treated in the game theoretic framework: just as one of a set of Pareto optimal solutions or cooperative game theory is a more promising approach? This research is based on results proving the existence of a nonempty Kcore, that is, the set of allocations acceptable for the family K of all feasible coalitions, for the case when this family is a set of subtrees of a tree. A wide range of real situations in resource management, which include optimal water, gas and electricity allocation problems can be modeled using this class of games. Thus, the present research is pursuing two goals: 1. optimality and 2. stability. Firstly, we suggest to players to unify their resources and then we optimize the total payoff using some standard LP technique. The same unification and optimization can be done for any coalition of players, not only for the total one. However players may object unification of resources. It may happen when a feasible coalition can guarantee a better result for every coalitionist. Here we obtain some stability conditions which ensure that this cannot happen for