Intertemporal Choice of Fuzzy Soft Sets

This paper first merges two noteworthy aspects of choice. On the one hand, soft sets and fuzzy soft sets are popular models that have been largely applied to decision making problems, such as real estate valuation, medical diagnosis (glaucoma, prostate cancer, etc.), data mining, or international trade. They provide crisp or fuzzy parameterized descriptions of the universe of alternatives. On the other hand, in many decisions, costs and benefits occur at different points in time. This brings about intertemporal choices, which may involve an indefinitely large number of periods. However, the literature does not provide a model, let alone a solution, to the intertemporal problem when the alternatives are described by (fuzzy) parameterizations. In this paper, we propose a novel soft set inspired model that applies to the intertemporal framework, hence it fills an important gap in the development of fuzzy soft set theory. An algorithm allows the selection of the optimal option in intertemporal choice problems with an infinite time horizon. We illustrate its application with a numerical example involving alternative portfolios of projects that a public administration may undertake. This allows us to establish a pioneering intertemporal model of choice in the framework of extended fuzzy set theorie

A multifactor approach to the social discount rate

This work focuses on the appraisal of public and environmental projects and, more specifically, on the calculation of the social discount rate (SDR) for this kind of very long-term investment projects. As a rule, we can state that the instantaneous discount rate must be equal to the hazard rate of the public good or to the mortality rate of the population that the project is intended to. The hazard can be due to technical failures of the system, but, in this paper, we are going to consider different independent variables that can cause the hazard. That is, we are going to consider a multivariate hazard rate. In our empirical application, the Spanish forest surface will be the system and the forest fire will be the fail that can be caused by several factors. The aim of this work is to integrate the different variables that produce the fail in the calculation of the SDR from a multivariate hazard rate approach

Fuzzy soft sets: a model for making choices in an intertemporal framework

[EN]This paper introduces a model where the options are characterized by one fuzzy soft set in each of an indefinite number of periods. This model extends the standard case of fuzzy soft sets. We explain how to associate a characteristic fuzzy soft set with each model. Finally, a decision making procedure for the selection of alternatives is proposed. The target applications include portfolio selection in finance, environmental issues, et cetera

Hesitant Fuzzy Worth: an innovative ranking methodology for hesitant fuzzy subsets

Producción CientíficaWe introduce a novel methodology for ranking hesitant fuzzy sets. It builds on a recent, theoretically sound contribution in Social Choice. In order to justify the applicability of such analysis, we develop two real implementations: (i) new metarankings of world academic institutions that build on real data from three reputed agencies, and (ii) a new procedure for improving teaching performance assessments which we illustrate with real data collected by ourselves.Ministerio de Economía, Industria y Competitividad (Project ECO2012-31933)Ministerio de Economía, Industria y Competitividad (Project ECO2012-32178)Ministerio de Economía, Industria y Competitividad (Project CGL2008-06003-C03-03/CLI)Junta de Andalucía (Project P09-SEJ-05404

On the measurement of sociopolitical consensus in direct democracies: Proposal of indexes

We investigate the measurement of sociopolitical consensus in direct democracies by means of three novel Consensus Indexes. They are special cases of Approval Consensus Measures, a tool from social choice that evaluates the degree of cohesiveness in a fixed group of agents that vote on a list of issues. We perform a basic dynamic analysis of the Swiss votes in popular initiatives, in periods marked by the main reforms and political crisis along those years. We provide novel quantitative arguments to validate the hypotheses that those reorganizations had an impact in terms of sociopolitical consensus during the last decade in comparison with prior stages. In addition we study the cumulative consensus in Italian referendums since 1974. We also investigate to what extent our indexes reflect the existence of periods in the development of referendums as a constitutional praxis

On the measurement of sociopolitical consensus in direct democracies: Proposal of indexes

We investigate the measurement of sociopolitical consensus in direct democracies by means of three novel Consensus Indexes. They are special cases of Approval Consensus Measures, a tool from social choice that evaluates the degree of cohesiveness in a fixed group of agents that vote on a list of issues. We perform a basic dynamic analysis of the Swiss votes in popular initiatives, in periods marked by the main reforms and political crisis along those years. We provide novel quantitative arguments to validate the hypotheses that those reorganizations had an impact in terms of sociopolitical consensus during the last decade in comparison with prior stages. In addition we study the cumulative consensus in Italian referendums since 1974. We also investigate to what extent our indexes reflect the existence of periods in the development of referendums as a constitutional praxis

A Mathematical Analysis of the Improving Sequence Effect for Monetary Rewards

In this paper, we mathematically formalize the concept of improving sequence effect, which is one of the main anomalies of the discounted utility model [1]. The improving sequence effect implies a preference for a given sequence of outcomes, which increase over time, and has been empirically demonstrated for both monetary and nonmonetary results (hedonic experiences and health-related outputs). Nevertheless, to date, there is no mathematical treatment of this anomaly in the context of intertemporal choice, which allows us to relate this paradox to other anomalies, such as the delay and magnitude effects. In this way, the present manuscript has filled this gap. More specifically, we have proved that the improving sequence effect for monetary rewards cannot be rationalized by using a separable discount function but only by considering a non-separable discount function. Moreover, under certain conditions, we have proved that the delay and magnitude effects are necessary conditions for the existence of the improving sequence effect

Incorporación de TIC basadas en Wolfram Mathematica a las asignaturas de Matemáticas del primer curso de las titulaciones de Economía y Empresa

Memoria ID-145. Ayudas de la Universidad de Salamanca para la innovación docente, curso 2019-2020