Open Access
An axiomatic analysis of ranking sets under simple categorization
(Springer, 2012) Alcantud, José Carlos R.; Arlegi Pérez, Ricardo; Economía; Ekonomia
This paper contributes to the axiomatization of additive rules for ranking sets of objects under the psychological principle of categorization. Firstly we proceed with the case where the elements in the sets are categorized into at most three groups, namely good (with value 1), neutral (with value 0), and bad (with value−1). Secondly, we solve the case where there are only good and neutral elements. In both instances the evaluation of the sets is purely additive. Lastly, we show that dropping one of the axioms in our general characterization produces an axiomatization of the more general class of evaluations where good and bad elements are weighted differently. Areas of research in Economics such as committee selection problems, hedonic games and matching are among the ranking sets models where our results could potentially be applied.
Open Access
Fair competition design
(2018) Arlegi Pérez, Ricardo; Dimitrov, Dinko; Ekonomia; Institute for Advanced Research in Business and Economics - INARBE; Economía
We study the impact of two basic principles of fairness on the structure of competition systems and perform our analysis by focusing on sports competitions. The first principle states that equally strong players should have the same chances of being the final winner, while the second principle requires that the competition system should not favor weaker players. We apply these requirements to a class of competitions which includes, but is not limited to, the sport tournament systems that are most commonly used in practice, such as round-robin tournaments and different kinds of knockout competitions, and we characterize the structures satisfying these requirements. In our results, a new competition structure that we call an antler is found to play a referential role. Finally, we show that the class of fair competition systems becomes rather small when both fairness principles are jointly applied.
Open Access
Power set extensions of dichotomous preferences
(Elsevier, 2016) Arlegi Pérez, Ricardo; Dimitrov, Dinko; Economía; Ekonomia
This paper is devoted to the study of how to extend a dichotomous partition of a universal set X into good and bad objects to an ordering on the power set of X. We introduce a family of rules that naturally take into account the number of good objects and the number of bad objects, and provide axiomatic characterizations of two rules that are particularly appealing when it comes to compating sets in which the good
Open Access
A theory of choice under internal conflict
(2012) Arlegi Pérez, Ricardo; Teschl, Miriam; Economía; Ekonomia
In this paper we discuss, inspired by some psychological literature, that choices are the outcome of the interplay of different, potentially conflicting motivations. We propose an axiomatic approach with two motivations, which we assume to be single-peaked over a certain given dimension. We first consider the case in which motivations are given and stable, and then introduce the possibility for motivations to change. We show first that in the no-motivation change case, certain choice behaviours that appear to be inconsistent from the standard rational choice point of view may be explained in our framework as the outcome of conflicting motivations. Afterwards, in the case of motivation change, we present two psychologically-flavoured assumptions about how motivations are influenced by choices. We show that, with some additional weak assumptions of rationality, motivation change leads to a smaller range of potentially inconsistent choices and not to a larger one as one may think. In particular, conflicts between two motivations can eventually be resolved by choosing different actions and consequently a definite and final preference for an action be revealed.
Open Access
Uncertainty with ordinal likelihood information
(Springer-Verlag, 2013) Alcalde Unzu, Jorge; Arlegi Pérez, Ricardo; Ballester Oyarzun, Miguel Ángel; Economía; Ekonomia
We present a model that is closely related to the so-called models of choice under complete uncertainty, in which the agent has no information about the probability of the outcomes. There are two approaches within the said models: the state space-based approach, which takes into account the possible states of nature and the correspondence between states and outcomes; and the set-based approach, which ignores such information, and solves certain difficulties arising from the state space-based approach. Kelsey (Int Econ Rev 34:297–308, 1993) incorporates into a state space-based framework the assumption that the agent has ordinal information about the likelihood of the states. This paper incorporates this same assumption into a set-based framework, thus filling a theoretical gap in the literature. Compared to the set-based models of choice under complete uncertainty we introduce the information about the ordinal likelihood of the outcomes while, compared to Kelsey’s approach, we incorporate the advantages of describing uncertainty environments from the set-based perspective. We present an axiomatic study that includes adaptations of some of the axioms found in the related literature and we characterize some rules featuring different combinations of information about the ordinal likelihood of the outcomes and information about their desirability.