dc.contributor.author Álvarez Faura, M. del Carme dc.contributor.author Messegué Buisan, Arnau dc.contributor.other Universitat Politècnica de Catalunya. Departament de Ciències de la Computació dc.date.accessioned 2018-03-09T08:25:09Z dc.date.available 2018-03-09T08:25:09Z dc.date.issued 2017-09-03 dc.identifier.citation Álvarez, C., Messegué, A. "Network creation games: structure vs anarchy". 2017. dc.identifier.uri http://hdl.handle.net/2117/114967 dc.description.abstract We study Nash equilibria and the price of anarchy in the classical model of Network Creation Games introduced by Fabrikant et al. In this model every agent (node) buys links at a prefixed price a > 0 in order to get connected to the network formed by all the n agents. In this setting, the reformulated tree conjecture states that for a > n, every Nash equilibrium network is a tree. Since it was shown that the price of anarchy for trees is constant, if the tree conjecture were true, then the price of anarchy would be constant for a > n. Moreover, Demaine et al. conjectured that the price of anarchy for this model is constant. Up to now the last conjecture has been proven in (i) the lower range, for a = O(n1-o¿) with o¿ = 1 and (ii) in the upper range, for a > 65n. In ¿log n contrast, the best upper bound known for the price of anarchy for the remaining range is 2O(vlog n). In this paper we give new insights into the structure of the Nash equilibria for different ranges of a and we enlarge the range for which the price of anarchy is constant. Regarding the upper range, we prove that every Nash equilibrium is a tree for a > 17n and that the price of anarchy is constant even for a > 9n. In the lower range, we show that any Nash equilibrium for a < n/C with C > 4, induces an o¿-distance-almost- uniform graph. dc.format.extent 22 p. dc.language.iso eng dc.rights.uri http://creativecommons.org/licenses/by-nc-sa/3.0/es/ dc.subject Àrees temàtiques de la UPC::Informàtica::Informàtica teòrica dc.subject.lcsh Computer networks -- Mathematical models dc.subject.lcsh Game theory dc.subject.other Nash equilibria dc.subject.other Network Creation Games dc.title Network creation games: structure vs anarchy dc.type External research report dc.subject.lemac Ordinadors, Xarxes d' -- Models matemàtics dc.subject.lemac Jocs, Teoria de dc.contributor.group Universitat Politècnica de Catalunya. ALBCOM - Algorismia, Bioinformàtica, Complexitat i Mètodes Formals dc.relation.publisherversion http://arxiv.org/abs/1706.09132 dc.rights.access Open Access local.identifier.drac 21983433 dc.description.version Postprint (published version) local.citation.author Álvarez, C.; Messegué, A
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