Isoscalar (T = 0) plus isovector (T = 1) pairing hamiltonian in LS-coupling, which is important for heavy N=Z nuclei, is solvable in terms of a O(8) algebra for some special values of the mixing parameter that measures the competition between T = 0 and T = 1 pairing. The O(8) algebra is generated, amongst others, by the S = 1, T = 0 and S = 0, T = 1 pair creation and annihilation operators . Shell model algebras, with only number conserving operators, that are complementary to theThe problem of classification of states for a given number of

Les pratiques industrielles et commerciales des banques coopératives coexistent avec des innovations sociales. À partir d’une enquête de terrain originale menée en France, l’article tente d’appréhender, en référence aux travaux de C. Vienney (1980, 1994), la capacité d’innovation sociale de ces banques relativement aux banques « SA ». Une différenciation utile est établie entre processus de banalisation et processus d’institutionnalisation. En s’intéressant à l’articulation entre règles, acteurs et organisation et à travers une analyse des services, des produits ou des dispositifs associés à ces différents types de banques, les auteurs soulignent la capacité des banques coopératives à répondre à des besoins non satisfaits par le marché, en privilégiant l’utilité du service sur la rentabilité. C’est aussi la capacité à mobiliser des acteurs collectifs dans le cadre de rapports de réciprocité entre les associés et l’organisation, en bref à faire vivre une démocratie économique, qui est mise en exergue.The industrial and commercial practices of cooperative banks co-exist with social innovations. Based on an original survey conducted in France, and pursuing the line of inquiry in Vienney's studies (1980, 1994), the article tries to assess the ability for social innovation of cooperative banks compared with conventional banks. A useful differentiation is made between the process of reverting into a mainstream firm and the process of institutionalization. By focusing on the relationship between regulations, actors and organization and examining the services, products and schemes associated with these different types of banks, the authors are able to highlight cooperative banks' ability to meet needs that are not fulfilled by the market by making service usefulness a higher priority than profitability. Another key factor that is pointed out is the ability to engage collective actors within the context of gift-exchange relations between members and the organization or, to put it more simply, economic democracy in action

A short review of the plethysm technique aiming to its application in finding branching rules for the reduction of an irreducible representation of a group under the restriction to one of its subgroups is given. The algebraic structure of the interacting boson model and some of its extensions is given together with the branching rules needed to classify their basis states, obtained by the use of plethysms.

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