Strategy-proof coalition formation

We analyze coalition formation problems in which a group of agents is partitioned into coalitions and agents' preferences only depend on the coalition they belong to. We study rules that associate to each profile of agents' preferences a partition of the society. We focus on strategyproof rules on restricted domains of preferences, as the domains of additively representable or separable preferences. In such domains, only single-lapping rules satisfy strategy-proofness, individual rationality, non-bossiness, and flexibility. Single-lapping rules are characterized by severe restrictions on the set of feasible coalitions. These restrictions are consistent with hierarchical organizations and imply that single-lapping rules always select core-stable partitions. Thus, our results highlight the relation between the non-cooperative concept of strategy-proofness and the cooperative concept of core-stability. We analyze the implications of our results for matching problem

Strategy-Proof Coalition Formation

We analyze coalition formation problems in which a group of agents is partitioned into coalitions and agents' preferences only depend on the coalition they belong to. We study rules that associate to each profile of agents' preferences a partition of the society. We focus on strategy-proof rules on restricted domains of preferences, as the domains of additively representable or separable preferences. In such domains, the only strategy-proof and individually rational rules that satisfy either Pareto efficiency or non-bossiness and flexibility are single-lapping rules. Single-lapping rules are characterized by severe restrictions on the set of feasible coalitions that are consisitent with hierarchical organizations. These restrictions are necessary and sufficient for the existence of a unique core-stable partition. This fact implies that single-lapping rules always select the associated unique core-stable partition. Thus, our results highlight the relation between the non-cooperative concept of strategy-proofness and the cooperative concept of uniqueness of core-stable partitions.Coalition Formation; Strategy-Proofness; Single-Lapping Property; Core-Stability; Matching Problems.

Strategy-proof coalition formation.

We analyze coalition formation problems in which a group of agents is partitioned into coalitions and agents' preferences only depend on the coalition they belong to. We study rules that associate to each profile of agents' preferences a partition of the society. We focus on strategyproof rules on restricted domains of preferences, as the domains of additively representable or separable preferences. In such domains, only single-lapping rules satisfy strategy-proofness, individual rationality, non-bossiness, and flexibility. Single-lapping rules are characterized by severe restrictions on the set of feasible coalitions. These restrictions are consistent with hierarchical organizations and imply that single-lapping rules always select core-stable partitions. Thus, our results highlight the relation between the non-cooperative concept of strategy-proofness and the cooperative concept of core-stability. We analyze the implications of our results for matching problems

School Choice with Transferable Students Characteristics

We consider a school choice problem where schools' priorities depend on transferable students' characteristics. A school choice algorithm selects for each profile of students' preferences over schools an assignment of students to schools and a final allocation of characteristics (an extended matching). We define the Student Exchange with Transferable Characteristics (SETC) class of algorithms. Each SETC always selects a constrained efficient extended matching. That is an extended matching that i) is stable according to the priorities generated by the final allocation of characteristics and ii) is not Pareto dominated by another stable extended matching. Every constrained efficient extended matching that Pareto improves upon a stable extended matching can be obtained via an algorithm in the SETC class. When students' characteristics are fully transferable, a specific algorithm in the SETC family is equivalent to the application of the Top Trade Cycle Algorithm starting from the Student Optimal Stable Matching

On single-peakedness and strategy-proofness: ties between adjacent alternatives

We extend the classical characterizations of social choice rules that satisfy strategy-proofness in the single-peaked domain of preferences by Moulin (Public Choice, 1980) and Barberà, Gul, and Stacchetti (Journal of Economic Theory, 1993) to multivalued social choice rules that admit either the selection of single alternatives or the selection of pairs of adjacent alternatives

Diagnostic efficacy of sentinel node biopsy in oral squamous cell carcinoma : cohort study and meta-analysis

Objectives: To evaluate the efficacy of sentinel node biopsy (SNB) in oral squamous cell carcinoma (OSCC). Design: A prospective study of a cohort of 25 consecutive patients with OSCC anatomopathological confirmation through biopsy, without oncological pre-treatment, in clinical stage T1-T4N0, of these 25 patients 14 were T1-T2N0. The absence of regional disease (N0) was determined by means of clinical exploration and cervical tomography (CT). To establish the overall sensitivity of the technique, a meta-analysis was carried out of 10 series published to February 2005 where SNB had been applied to head and neck cancer, adding our 14 T1-T2N0 cases, thus making a total of 260 patients. Results: Identification by SNB was accurate in 96% of the 25 cases, with a sensitivity of 66.7%. Analyzing only the T1-T2N0 cases (n=14), the accuracy was 100% with a sensitivity of 1 (CI 95%, 0.29-1.00). The overall sensitivity was 93%. The accuracy in identifying the sentinel node varied between 66% and 100%. The SN was identified in 251 of 260 cases, of those, 71 were true positive, 5 false negative and 175 true negative. The overall sensitivity was 93.4% (CI 95%, 85.3-97.8), with a specificity of 100% (CI 95%, 0.98-100). The weighted negative probability quotient was 0.176 (CI 0.103-0.301) and that of positive probability 24.75 (CI 95%, 10.8-56.71). The weighted diagnostic odds ratio was 183.71 (CI 95%, 59.36-568.56). If we accept that the prevalence of hidden regional disease is 30%, a negative sentinel node has 5% possibility of having hidden disease. Conclusions: Our data provide a certain degree of evidence that, due to its high sensitivity, the SNB procedure can be applied to the initial stages of OSCC

La Economía del Comportamiento en la asignatura de Teoría de Juegos: Experimentos en las aulas

El objetivo es introducir la economía experimental como herramienta pedagógica en la enseñanza de Teoría de Juegos para alumnos de los Grados en Economía y Doble Grado en Economía, Matemáticas y Estadística acercándoles a un análisis económico actual

Diseño de prácticas externas curriculares del Centro Universitario de la Defensa de San Javier en el marco del EEES. Una metodología innovadora

[SPA] Este trabajo presenta el proceso seguido por el Equipo de Innovación Docente de Prácticas Externas del Centro Universitario de la Defensa de San Javier para el desarrollo de las prácticas curriculares de los alumnos del Grado de Ingeniería y futuros oficiales del Ejército del Aire, que se impartirán dentro del nuevo modelo de enseñanza militar. La metodología propuesta se presenta como un ejemplo de adaptación a un nuevo modelo de enseñanza dentro del EEES que busca solventar deficiencias de modelos universitarios previos como eran la falta de especificación de las tareas en las prácticas o la realización de otras no vinculadas a la titulación (Ballesteros-Velázquez et al. 2001). Se propone una adaptación de los contenidos de las prácticas a partir de un análisis in situ, de los centros donde se realizarán y utilizando como criterio para la selección de puestos y tareas su vinculación con asignaturas del grado y a profesionales con distinto rango de responsabilidad y cualificación. Así, el alumno puede aprender a utilizar las competencias concretas y necesarias para ejercer su profesión, porque las recibe de profesionales que están aplicando capacidades distintas en función de la etapa de la vida laboral en la que se encuentran. [ENG] This paper presents the process followed by the teaching innovation team at the Defence University Centre in San Javier for the design of a traineeship for Industrial Organization Engineering students, future officers of the Air Force, according to the new military education programme. The traineeship design steps are described as a specific example of a methodology adapted to a new specialized education programme within the European Space for Higher Education (EEES) in order to solve the limitations of educational models previous to EEES (Ballesteros-Velázquez et al. 2001). The authors propose in situ monitoring on the part of lecturers in each of the centres where students will carry out their traineeship to properly identify tasks and adapt the traineeship contents linking them to the degree courses and to reference professionals at different stages of their career. In this way, the student can fully apply concrete and necessary competences in the particular area where he/she Will practise his/her profession