Competitive division of a mixed manna

A mixed manna contains goods (that everyone likes) and bads (that everyone dislikes), as well as items that are goods to some agents, but bads or satiated to others. If all items are goods and utility functions are homogeneous of degree 1 and concave (and monotone), the competitive division maximizes the Nash product of utilities (Gale–Eisenberg): hence it is welfarist (determined by the set of feasible utility profiles), unique, continuous, and easy to compute. We show that the competitive division of a mixed manna is still welfarist. If the zero utility profile is Pareto dominated, the competitive profile is strictly positive and still uniquely maximizes the product of utilities. If the zero profile is unfeasible (for instance, if all items are bads), the competitive profiles are strictly negative and are the critical points of the product of disutilities on the efficiency frontier. The latter allows for multiple competitive utility profiles, from which no single-valued selection can be continuous or resource monotonic. Thus the implementation of competitive fairness under linear preferences in interactive platforms like SPLIDDIT will be more difficult when the manna contains bads that overwhelm the goods

Split Cycle: A New Condorcet Consistent Voting Method Independent of Clones and Immune to Spoilers

We propose a Condorcet consistent voting method that we call Split Cycle. Split Cycle belongs to the small family of known voting methods that significantly narrow the choice of winners in the presence of majority cycles while also satisfying independence of clones. In this family, only Split Cycle satisfies a new criterion we call immunity to spoilers, which concerns adding candidates to elections, as well as the known criteria of positive involvement and negative involvement, which concern adding voters to elections. Thus, in contrast to other clone-independent methods, Split Cycle mitigates both "spoiler effects" and "strong no show paradoxes."Comment: 71 pages, 15 figures. Added a new explanation of Split Cycle in Section 1, updated the caption to Figure 2, the discussion in Section 3.3, and Remark 4.11, and strengthened Proposition 6.20 to Theorem 6.20 to cover single-voter resolvability in addition to asymptotic resolvability. Thanks to Nicolaus Tideman for helpful discussio

Argumentation Mining in User-Generated Web Discourse

The goal of argumentation mining, an evolving research field in computational linguistics, is to design methods capable of analyzing people's argumentation. In this article, we go beyond the state of the art in several ways. (i) We deal with actual Web data and take up the challenges given by the variety of registers, multiple domains, and unrestricted noisy user-generated Web discourse. (ii) We bridge the gap between normative argumentation theories and argumentation phenomena encountered in actual data by adapting an argumentation model tested in an extensive annotation study. (iii) We create a new gold standard corpus (90k tokens in 340 documents) and experiment with several machine learning methods to identify argument components. We offer the data, source codes, and annotation guidelines to the community under free licenses. Our findings show that argumentation mining in user-generated Web discourse is a feasible but challenging task.Comment: Cite as: Habernal, I. & Gurevych, I. (2017). Argumentation Mining in User-Generated Web Discourse. Computational Linguistics 43(1), pp. 125-17

Essays on optimal spectrum management for expanding wireless communications

Wireless communications are experiencing an unprecedented expansion. The increasing mobility of the communication society and the pace of technological change are growing pressure for more spectrum to support more users, more uses and more capacity. Thus, spectrum management has become an extremely important part of wireless communications. A few regulators are changing their traditional ‘command and control’ approach. Nevertheless, many features of optimal spectrum management are still widely discussed. This work is aimed at contributing to that discussion. The key insight is that spectrum management can benefit from more liberal spectrum sharing. This work set out to answer three main research questions: (i) whether there is a theoretical framework which can be used to analyze and guide spectrum policy reform, when moving from a traditional ‘command and control’ regime to a market-inspired one; (ii) whether it is possible to design a plausible mechanism which can promote efficient allocation and assignment of spectrum commons; (iii) whether (and how) technological developments could enable band sharing methods outside the traditional management framework and without harmful interference. The literature on transition economics and policy was used to help answer the first research question. Evidence from liberalizing countries was positively analyzed to discuss reforms of spectrum allocation and assignment methods. Most countries have adopted strategies that gradually change their spectrum policies and started by using more liberal methods to assign spectrum. It is also argued that future spectrum reforms might benefit from insights presented in the transition economics literature. A translation of a model on cartel quotas under majority rule is proposed to answer the second research question. The work verifies, firstly, that an analogous set of properties is satisfied under our assumptions and that the median-index theorem applies, mutatis mutandis, to our setting. Thus firms bidding to acquire spectrum commons contribute a minimum amount of their wealth; the sum of contributions offered is then compared to other bids for the same spectrum, which is allocated to the highest bidder. The last research question considers novel ways of spectrum sharing that might be enabled by technological developments. The work explores contributions, from various research areas, regarding management of scarce resources. Those contributions are discussed with respect to shared spectrum access. It is suggested that spectrum management might benefit from methods which enable the management of pooled (intermittent) demands for access, especially methods in line with fair sojourn protocols

Of Myth and Memory: Collective Memory in the French World War II Museum

This thesis examines the complex mechanics of collective memory in France through a study of museums dedicated to World War II. Through a chronological analysis of museums that have emerged over the past seventy years, I endeavor to connect the evolution of the French war museum to the creation, propagation and ultimate disintegration of the ‘Resistance Myth,’ a national wartime narrative propagated by the French government in the postwar period. This study concludes with an analysis of the current status of the WWII museum as an educative and commemorative institution that presents the Resistance in a restructured though not entirely unprecedented light

Split Cycle: A New Condorcet Consistent Voting Method Independent of Clones and Immune to Spoilers

We introduce a new Condorcet consistent voting method, called Split Cycle. Split Cycle belongs to the small family of known voting methods satisfying independence of clones and the Pareto principle. Unlike other methods in this family, Split Cycle satisfies a new criterion we call immunity to spoilers, which concerns adding candidates to elections, as well as the known criteria of positive involvement and negative involvement, which concern adding voters to elections. Thus, relative to other clone-independent Paretian methods, Split Cycle mitigates “spoiler effects” and “strong no show paradoxes.

A Noncooperative Approach to Bankruptcy Problems with an Endogenous Estate

We introduce a new class of bankruptcy problems in which the value of the estate is endogenous and depends on agents'' investment decisions. There are two investment alternatives: investing in a company and becoming a shareholder (risky asset) and depositing money into a savings account (risk-free asset). Bankruptcy is a possible event only for the risky asset. We define a game between agents each of which aims to maximize his expected payoff by choosing an investment alternative and a company management which aims to maximize profits by choosing a bankruptcy rule. There are two types of agents in our basic model, who are differentiated by their incomes. We, first, consider three well-known bankruptcy rules: the proportional rule, the constrained equal awards rule and the constrained equal losses rule. We show that there always exists a pure strategy subgame perfect Nash equilibrium, which involves the proportional rule. This result is independent of the income distribution in the economy and holds even under one-sided uncertainty on the income distribution. Moreover, if the company optimally chooses the return rate to be paid to investors, the unique subgame perfect Nash equilibrium involves the proportional rule. We also extend our model in two dimensions: (i) to a larger set of rules containing the Talmud rule and (ii) to two companies competing over potential investors.Economics (Jel: A)

Do Rankings Reflect Research Quality?

Publication and citation rankings have become major indicators of the scientific worth of universities and countries, and determine to a large extent the career of individual scholars. We argue that such rankings do not effectively measure research quality, which should be the essence of evaluation. For that reason, an alternative ranking is developed as a quality indicator, based on membership on academic editorial boards of professional journals. It turns out that especially the ranking of individual scholars is far from objective. The results differ markedly, depending on whether research quantity or research quality is considered. Even quantity rankings are not objective; two citation rankings, based on different samples, produce entirely different results. It follows that any career decisions based on rankings are dominatedby chance and do not reflect research quality. Instead of propagating a ranking based on board membership as the gold standard, we suggest that committees make use of this quality indicator to find members who, in turn, evaluate the research quality of individual scholars.rankings, universities, scholars, publications, citations

Sign, then Ratify : Negotiating under Threshold Constraints

The procedure for implementing any international treaty necessarily involves two steps. The negotiation phase which culminates in the signature of the treaty is followed by a ratification phase. This last phase is governed by a rule which determines how far the ratification process has to advance before the treaty can come into effect. The purpose of this paper is to analyse, using a game theoretical approach, the possible consequences of this minimum participationrule for the ratification phase and for the negotiation phase. I consider the case of International Environmental Agreements in which, during the negotiation phase, the different parties have to decide on the level of a global target and on how to share the efforts necessary to reach it. I use a cooperative approach to define what is called the threshold value (T-value). For a given coalition of parties, the T-value gives the expected outcome of the negotiation oversharing a global target, when the parties take into account the minimum participation rule. Given this T-value, I use a non-cooperative approach to determine which coalition will sign the agreement and what will be its global target. The minimum participation constraint has in fact no impact on the ratification phase because it is always better to refuse to sign rather thanto sign and then refuse to ratify. However, I show that the minimum participation constraint can modify the outcome of the negotiation phase. Indeed, it plays a role in a mechanism which can be used by a coalition to signal its leadership commitment. I analyse the conditions under which, at the equilibrium, the leading coalition can provoke an expansion of the signingcoalition