Random generation of finitely generated subgroups of a free group

We give an efficient algorithm to randomly generate finitely generated subgroups of a given size, in a finite rank free group. Here, the size of a subgroup is the number of vertices of its representation by a reduced graph such as can be obtained by the method of Stallings foldings. Our algorithm randomly generates a subgroup of a given size n, according to the uniform distribution over size n subgroups. In the process, we give estimates of the number of size n subgroups, of the average rank of size n subgroups, and of the proportion of such subgroups that have finite index. Our algorithm has average case complexity \O(n) in the RAM model and \O(n^2\log^2n) in the bitcost model

Exponential inequalities for self-normalized martingales with applications

We propose several exponential inequalities for self-normalized martingales similar to those established by De la Pe\~{n}a. The keystone is the introduction of a new notion of random variable heavy on left or right. Applications associated with linear regressions, autoregressive and branching processes are also provided.Comment: Published in at http://dx.doi.org/10.1214/07-AAP506 the Annals of Applied Probability (http://www.imstat.org/aap/) by the Institute of Mathematical Statistics (http://www.imstat.org

Foreign Direct Investment in Africa: What are the Key Factors of Attraction aside from Natural Resources?

This input, essentially empirical by nature, analyses the FDI determinants in Africa independently from the already clearly identified attraction of natural resources. Do powers of anticipation as to the general prospects for these economies influence incoming flows of capital? What role is played by socio-political instability connected to the social consequences caused by conflicts? Are the processes of regionalization enhancing the appeal of countries that are going down that path? From a panel of 28 African countries, the results from estimations obtained using the Hausman-Taylor method of instrumental variables show that the impact of projections on any ongoing decision to invest in the continent is not statistically significant. Our results also show that, although negative, the direct correlation between social risk, a proxy of socio-political instability, and flows of foreign investment is not systematically significant.. However, the fact remains that these instabilities undermine national competencies (human capital) and compound certain ills such as HIV/Aids, whose impact on foreign investment increases along a negative curve in the presence of social risk. However, the simultaneous introduction of regionalization processes into our estimations tends to lower the adverse effects of instability on certain explicative FDI variables.Foreign Direct Investment (FDI), African economies, projections/anticipations, risk and socio-political instability, regional integration

Taramoin : tradition orale et tradition écrite à l’école maternelle, Nouvelle-Calédonie, par TRÂN Ngọc-Anh

Présentation d’un travail de recherche sur l’enseignent scolaire de la langue française en Nouvelle-Calédonie Mots clés : École maternelle. Enseignement bi-plurilingue. Français langue de scolarisation. Français langue seconde. Nouvelle-Calédonie.  Taramoin : oral tradition and written tradition at primary school, New Caledonia, by TRÂN Ngọc-Anh Abstract : Presentation of a research on the French language for school teaching in New Caledonia Keywords: Nursery school. Bi-plurilingual education. French language for teaching/learning. French as a second language. New Caledonia.  Taramoin: tradição oral e tradição escrita no ensino fundamental 1, Nova Caledônia, por TRÂN Ngọc-Anh Resumo: Apresentação de uma pesquisa sobre a língua francesa para o ensino escolar na Nova Caledônia. Palavras-chave: Ensino fudamental 1. Educação bi-multilíngue. Língua francesa para ensino / aprendizagem. Francês como segunda língua. Nova Caledônia.  Taramoin: tradición oral y tradición escrita en la escola, Nueva Caledonia, por TRÂN Ngọc-Anh Resumen: Presentación de una investigación sobre el idioma francés para la enseñanza escolar en Nueva Caledonia. Palabras-clave: Escola. Educación bilingüe. Lengua francesa para la enseñanza / aprendizaje. El francés como segunda lengua. Nueva Caledonia

FTPL and war reparations : the French and German monetary experiences in the Interwar period (In French)

In this paper, we try to investigate the rationale for using the Fiscal Theory of the Price Level (FTPL) as a relevant theoretical framework for analysing French and German monetary experiences in the Interwar period. This approach involves considering the evolution of public debt as the main anchoring factor of the price level through the respect of the intertemporal budget constraint by the public sector. French and german stylized facts, especially during the 1919-1926 period seem at first glance to be in accordance with this relationship. A more precise analysis of the monetary policy implementation suggests, however, that only the weak form (instead of the strong one) of the FTPL could have prevailed. Indeed, the requirement of stable public debt dynamics went hand in hand with the domination of monetary policy by fiscal policy.inflation, public debt, FTPL

Bartolomé Bennassar (1929-2018)

© Archives BHCE Bartolomé Bennassar (1929-2018), professeur à l'université de Toulouse - Le Mirail, dont il a été le président de 1978 à 1980, a consacré ses recherches à l'Espagne, à son passé, à son mode de vie, à ses passions. Deux périodes ont retenu son attention : celle de la prépondérance —le siècle d'or— et celle de la guerre civile et de Franco. Un livre domine la première période : la thèse sur Valladolid dirigée par Fernand Braudel et soutenue en 1967. Qu'on ne s'y trompe pas : c'e..

A bio-economic model for the ecosystem-based management of the coastal fishery in French Guiana

This paper offers a theoretical and empirical modeling for ecosystem-based fishery management (EBFM). A multi-species and multi-fleets model integrating Lokta-Volterra trophic dynamics and profit functions is developed for the coastal fishery of French Guiana. This small-case fishery constitutes a challenging example with high fish biodiversity, several non selective fleets and a potentially increasing local food demand due to demographic pressure. The dynamic model is calibrated with thirteen species and four fleets using catch and effort data on a monthly basis from 2006 to 2009. Several contrasting fishing scenarios including status quo, total closure, economic and viable strategies are simulated and compared from both biodiversity preservation and socio-economic performance viewpoints. We show that fishing outputs including food supply and profitability of fleets can be sustained although a significant loss of biodiversity cannot be avoided.Small-scale fishery, biodiversity, sustainability, profitability, food security, multi-species, multi-fleets