Coactions of Hopf C*-bimodules

Coactions of Hopf C*-bimodules simultaneously generalize coactions of Hopf C*-algebras and actions of groupoids. Following an approach of Baaj and Skandalis, we construct reduced crossed products and establish a duality for fine coactions. Examples of coactions arise from Fell bundles on groupoids and actions of a groupoid on bundles of C*-algebras. Continuous Fell bundles on an etale groupoid correspond to coactions of the reduced groupoid algebra, and actions of a groupoid on a continuous bundle of C*-algebras correspond to coactions of the function algebra.Comment: 44 pages, to appear in the Journal of Operator theor

Farmer's Eye and Breeder's Eye - Fields of Knowledge Exchange as a Condition of a Participatory Breeding Approach

With the change to organic agriculture, the diversity of local conditions becomes more important. Local adapted varieties are necessary. But breeding for this demand is not profitable for a conventional breeding strategy. An alternative can be a participatory breeding approach (PPB). Evolved in the context of international development cooperation, this approach is increasingly discussed in the European context. Communication between farmers and breeders is a key issue in participatory breeding. Farmer`s and breeder`s eye have different perspectives on the plants and different knowledge gained through experience. Those perspectives and experiences need to be exchanged. As an outcome of the investigation of “The breeder`s eye” on the example of the crossbreeding of self-fertilizing cereals from a knowledge sociology perspective three levels of consciousness could be described: vegetational consciousness, generational consciousness and consciousness in hereditary flow (Timmermann, 2006). The framework of these three levels allows to understand the various levels of breeding behaviour and how the breeders learn and develop their breeding practices. Based on this results, fields of knowledge exchange between farmer and breeder, their limits and possibilities for further development can be worked out

Measured quantum groupoids associated to proper dynamical quantum groups

Dynamical quantum groups were introduced by Etingof and Varchenko in connection with the dynamical quantum Yang-Baxter equation, and measured quantum groupoids were introduced by Enock, Lesieur and Vallin in their study of inclusions of type II_1 factors. In this article, we associate to suitable dynamical quantum groups, which are a purely algebraic objects, Hopf C*-bimodules and measured quantum groupoids on the level of von Neumann algebras. Assuming invariant integrals on the dynamical quantum group, we first construct a fundamental unitary which yields Hopf bimodules on the level of C*-algebras and von Neumann algebras. Next, we assume properness of the dynamical quantum group and lift the integrals to the operator algebras. In a subsequent article, this construction shall be applied to the dynamical SU_q(2) studied by Koelink and Rosengren.Comment: revised version to appear in Journal of Noncommutative geometr

Free dynamical quantum groups and the dynamical quantum group SU_q(2)

We introduce dynamical analogues of the free orthogonal and free unitary quantum groups, which are no longer Hopf algebras but Hopf algebroids or quantum groupoids. These objects are constructed on the purely algebraic level and on the level of universal C*-algebras. As an example, we recover the dynamical SU_q(2) studied by Koelink and Rosengren, and construct a refinement that includes several interesting limit cases.Comment: clarified relation to general Hopf algebroid

Contributive Justice: An exploration of a wider provision of meaningful work

Extreme inequality of opportunity leads to a number of social tensions, inefficiencies and injustices. One issue of increasing concern is the effect inequality is having on people’s fair chances of attaining meaningful work, thus limiting opportunities to make a significant positive contribution to society and reducing the chances of living a flourishing life and developing their potential. On a global scale we can observe an increasingly uneven provision of meaningful work, raising a series of ethical concerns that need detailed examination. The aim of this article is to explore the potential of a normative framework based upon the idea of contributive justice to defend a fairer provision of meaningful work

The Fell compactification and non-Hausdorff groupoids

A compactification of Fell is applied to locally compact non-Hausdorff groupoids and yields locally compact Hausdorff groupoids. In the etale case, this construction provides a geometric picture for the left-regular representations introduced by Khoshkam and Skandalis.Comment: 7 page