Sat, 26 Jul 2008 08:08:30 BST CiteULike: AbnerCYH economic http://www.citeulike.org/user/AbnerCYH/tag/economic CiteULike.org en-gb Copyright © 2004-2008 citeulike.org http://www.citeulike.org/user/AbnerCYH/article/2557331 <i>(2008), pp. 74-83.</i> Succinct approximate convex pareto curves Ilias Diakonikolas Mihalis Yannakakis (2008), pp. 74-83. 2008-03-19T08:12:31-00:00 2008 74 83 Society for Industrial and Applied Mathematics algorithms economic optimization http://www.citeulike.org/user/AbnerCYH/article/2501046 <i>Operations Research Letters, Vol. 36, No. 2. (March 2008), pp. 173-176.</i><br /><br />The principal aim of this paper is to show that every weakly efficient solution of a lexicographic quasiconvex multicriteria optimization problem actually is an efficient (Pareto) solution of a reduced problem, obtained from the original one by selecting a certain number of criteria, not exceeding the Helly number of the solution space. Involving the Helly number in Pareto reducibility Nicolae Popovici doi:10.1016/j.orl.2007.09.002 Operations Research Letters, Vol. 36, No. 2. (March 2008), pp. 173-176. 2008-03-10T14:12:33-00:00 2008 Operations Research Letters 36 2 173 176 algorithms economic game http://www.citeulike.org/user/AbnerCYH/article/2396502 <i>Mathematical Programming, Vol. 113, No. 1. (22 May 2008), pp. 95-131.</i><br /><br />Abstract  This paper explores the structure of optimal investment strategies using stochastic programming and duality theory in investment portfolios containing options for a hedge fund manager who attempts to beat a benchmark. Explicit optimal conditions for option investments are obtained for several models. The duality of option investment strategies for hedge funds José Rodríguez-Mancilla William Ziemba doi:10.1007/s10107-007-0198-1 Mathematical Programming, Vol. 113, No. 1. (22 May 2008), pp. 95-131. 2008-02-18T22:08:38-00:00 2008 Mathematical Programming 113 1 95 131 economic math http://www.citeulike.org/user/AbnerCYH/article/1450478 <i>Economica, Vol. 74, No. 295. (August 2007), pp. 566-567.</i> Computability, Complexity and Constructivity in Economic Analysis. Edited by K. VELA VILLAPILLAI Steven Durlauf doi:10.1111/j.1468-0335.2007.00542.x Economica, Vol. 74, No. 295. (August 2007), pp. 566-567. 2007-07-12T00:29:43-00:00 2007 Economica 0013-0427 74 295 566 567 Blackwell Publishing algorithms complex complexity economic http://www.citeulike.org/user/AbnerCYH/article/1824355 <i>(24 Oct 2007)</i><br /><br />Boolean Delay Equations (BDEs) are semi-discrete dynamical models with Boolean-valued variables that evolve in continuous time. Systems of BDEs can be classified into conservative or dissipative, in a manner that parallels the classification of ordinary or partial differential equations. Solutions to certain conservative BDEs exhibit growth of complexity in time. They represent therewith metaphors for biological evolution or human history. Dissipative BDEs are structurally stable and exhibit multiple equilibria and limit cycles, as well as more complex, fractal solution sets, such as Devil's staircases and “fractal sunbursts“. All known solutions of dissipative BDEs have stationary variance. BDE systems of this type, both free and forced, have been used as highly idealized models of climate change on interannual, interdecadal and paleoclimatic time scales. BDEs are also being used as flexible, highly efficient models of colliding cascades in earthquake modeling and prediction, as well as in genetics. In this paper we review the theory of systems of BDEs and illustrate their applications to climatic and solid earth problems. The former have used small systems of BDEs, while the latter have used large networks of BDEs. We moreover introduce BDEs with an infinite number of variables distributed in space (“partial BDEs“) and discuss connections with other types of dynamical systems, including cellular automata and Boolean networks. This research-and-review paper concludes with a set of open questions. Boolean Delay Equations: A simple way of looking at complex systems Michael Ghil Ilya Zaliapin Barbara Coluzzi (24 Oct 2007) 2007-10-26T09:16:51-00:00 2007 complex economic logic math http://www.citeulike.org/user/AbnerCYH/article/1778523 <i>Algorithmica</i><br /><br />Abstract   We study the complexity issues for Walrasian equilibrium in a special case of combinatorial auction, called single-minded auction, in which every participant is interested in only one subset of commodities. Chen et al. (J. Comput. Syst. Sci. 69(4): 675–687, 2004) showed that it is NP-hard to decide the existence of a Walrasian equilibrium for a single-minded auction and proposed a notion of approximate Walrasian equilibrium called relaxed Walrasian equilibrium. We show that every single-minded auction has a relaxed Walrasian equilibrium that satisfies at least two-thirds of the participants, proving a conjecture posed in Chen et al. (J. Comput. Syst. Sci. 69(4): 675–687, 2004). Motivated by practical considerations, we introduce another concept of approximate Walrasian equilibrium called weak Walrasian equilibrium. We show NP-completeness and hardness of approximation results for weak Walrasian equilibria. In search of positive results, we restrict our attention to the tollbooth problem (Guruswami et al. in Proceedings of the Symposium on Discrete Algorithms (SODA), pp. 1164–1173, 2005), where every participant is interested in a single path in some underlying graph. We give a polynomial time algorithm to determine the existence of a Walrasian equilibrium and compute one (if it exists), when the graph is a tree. However, the problem is still NP-hard for general graphs. Walrasian Equilibrium: Hardness, Approximations and Tractable Instances Ning Chen Atri Rudra doi:10.1007/s00453-007-9103-9 Algorithmica 2007-10-17T06:35:38-00:00 Algorithmica algorithms complexity economic game optimization http://www.citeulike.org/user/AbnerCYH/article/623810 <i>(10 May 2006)</i><br /><br />A simple computer simulation model of a closed market on a fixed network with free flow of goods and money is introduced. The model contains only two variables : the amount of goods and money beside the size of the system. An initially flat distribution of both variables is presupposed. We show that under completely random rules, i.e. through the choice of interacting agent pairs on the network and of the exchange rules that the market stabilizes in time and shows diversification of money and goods. We also indicate that the difference between poor and rich agents increases for small markets, as well as for systems in which money is steadily deduced from the market through taxation. Model of Wealth and Goods Dynamics in a Closed Market Marcel Ausloos Andrzej Pekalski (10 May 2006) 2006-05-11T20:13:40-00:00 2006 dynamics economic