On Nichols algebras over PGL(2,q) and PSL(2,q)

We compute necessary conditions on Yetter-Drinfeld modules over the groups \mathbf{PGL}(2,q)=\mathbf{PGL}(2,\FF_q) and \mathbf{PSL}(2,q)=\mathbf{PSL}(2,\FF_q) to generate finite dimensional Nichols algebras. This is a first step towards a classification of pointed Hopf algebras with group of group-likes isomorphic to one of these groups. As a by-product of the techniques developed in this work, we prove that there is no non-trivial finite-dimensional pointed Hopf algebra over the Mathieu groups $M_{20}$ and $M_{21}=\mathbf{PSL}(3,4)$.Comment: Minor change

Respuestas de cultivares de trigo pan (Triticum aestivum L) a la competencia de malezas

Se analizó la respuesta de distintos cultivares de trigo pan (Triticum aestivum L.) a la competencia de malezas. Los tratamientos consistieron en una combinación factorial de 4 cultivares (Baguette 10, Baguette 12, Buck Guapo y Buck Charrúa) por 2 sistemas de enmalezado (con y sin malezas durante todo el ciclo del cultivo) mas 1 tratamiento de malezas sin cultivo. Las principales malezas fueron: Lamminun amplexicaule ("ortiga mansa"); Centaurea solstitialis ("abrepuños amarillo"); Chenopodium album ("quinoa"). La producción de materia seca aérea de malezas sin la presencia del cultivo fue de 1.900 kg/ha cuando el trigo se encontró en el estado del cultivo de 3 nudos detectables; allí se produjo una reducción del 73,1% del crecimiento de las malezas, pero sobre ello hubo diferencias entre los cultivares ensayados. Las malezas provocaron pérdidas de rendimiento de grano del 11,7%, lo que se debió principalmente a la disminución del número de espigas a cosecha. Ningún otro componente de rendimiento resulto afectado. Sobre esa pérdida de producción no hubo diferencias significativas (p= 0,05) entre los 4 cultivares ensayados. Los índices de agresividad calculados con la materia seca aérea de malezas y cultivo con y sin mutua competencia fueron positivos, pero tampoco se encontraron diferencias significativas (p= 0,05) debidas al factor cultivar. Director: Fernández, Miguel A.              García Fernando D

Interwoven migration narratives: identity and social representations in the Lusophone world

First published online: 17 Oct 2016This article provides an exploratory analysis of the life narratives of migrants in the Portuguese-speaking world. By interweaving the life experiences of eight participants in three thematic clusters – ‘shared past’, language and sense of community – we propose a critique of the deep-seated idea of the Lusophone space as a community constructed by the harmonious conviviality of different countries and people. Drawing on contributions from cultural studies, social psychology, anthropology and sociology, we first aim to give voice to the human subjects who embark on migrations and then to understand how the engendered process of identity construction is framed by their social world, simultaneously reframing it. Thus, we aim at shedding light on the ways in which aspects of the political discourses on Lusophony are used (and are instrumental) to the migrants’ identity narrative (re)construction.This work was supported by Fundacao para a Ciencia e a Tecnologia: [Grant Number PTDC/CCI-COM/105100/2008]

Finite-dimensional pointed Hopf algebras with alternating groups are trivial

It is shown that Nichols algebras over alternating groups A_m, m>4, are infinite dimensional. This proves that any complex finite dimensional pointed Hopf algebra with group of group-likes isomorphic to A_m is isomorphic to the group algebra. In a similar fashion, it is shown that the Nichols algebras over the symmetric groups S_m are all infinite-dimensional, except maybe those related to the transpositions considered in [FK], and the class of type (2,3) in S_5. We also show that any simple rack X arising from a symmetric group, with the exception of a small list, collapse, in the sense that the Nichols algebra of (X,q) is infinite dimensional, for q an arbitrary cocycle. arXiv:0904.3978 is included here.Comment: Changes in version 7: We eliminate the Subsection 3.3 and references to type C throughout the paper. We remove Lemma 3.24, Proposition 3.28 and Example 3.29 (old numbering), since they are not needed in the present paper. Several minor mistakes are corrected. The proof of Step 2 in Theorem 4.1 is adjuste

Pointed Hopf algebras over some sporadic simple groups

Any finite-dimensional complex pointed Hopf algebra with group of group-likes isomorphic to a sporadic group, with the possible exception of the Fischer groups Fi22, the Baby Monster B and the Monster M, is a group algebra.Comment: 4 pages, v4: Minor changes, more groups include