A Katsylo theorem for sheets of spherical conjugacy classes

We show that, for a sheet or a Lusztig stratum S containing spherical conjugacy classes in a connected reductive algebraic group G over an algebraically closed field in good characteristic, the orbit space S/G is isomorphic to the quotient of an affine subvariety of G modulo the action of a finite abelian 2-group. The affine subvariety is a closed subset of a Bruhat double coset and the abelian group is a finite subgroup of a maximal torus of G. We show that sheets of spherical conjugacy classes in a simple group are always smooth and we list which strata containing spherical classes are smooth

Intergenerational Education for Social Inclusion and Solidarity: The Case Study of the EU Funded Project "Connecting Generations"

This paper reflects on lessons learned from a validated model of international collaboration based on research and practice. During the European Year for Active Ageing, a partnership of seven organizations from the European Union plus Turkey implemented the Lifelong Learning Programme partnership “Connecting Generations‘ which involved universities, non-governmental organizations, third age Universities and municipalities in collaboration with local communities. Reckoning that Europe has dramatically changed in its demographic composition and is facing brand new challenges regarding intergenerational and intercultural solidarity, each partner formulated and tested innovative and creative practices that could enhance better collaboration and mutual understanding between youth and senior citizens, toward a more inclusive Europe for all. Several innovative local practices have experimented, attentively systematized and peer-valuated among the partners. On the basis of a shared theoretical framework coherent with EU and Europe and Training 2020 Strategy, an action-research approach was adopted throughout the project in order to understand common features that have been replicated and scaled up since today

Affine hyperplane arrangements and Jordan classes

We study the geometry of the stratification induced by an affine hyperplane arrangement H on the quotient of a complex affine space by the action of a discrete group preserving H. We give conditions ensuring normality or normality in codimension 1 of strata. As an application, we provide the list of those categorical quotients of closures of Jordan classes and of sheets in all complex simple algebraic groups that are normal. In the simply connected case, we show that normality of such a quotient is equivalent to its smoothness.Comment: Major revision. More details added in some remarks and proofs. Proposition 10.10 correcte

On Jordan classes for Vinberg's theta-groups

Popov has recently introduced an analogue of Jordan classes (packets, or decomposition classes) for the action of a theta-group (G_0,V), showing that they are finitely-many, locally-closed, irreducible unions of G_0-orbits of constant dimension partitioning V. We carry out a local study of their closures showing that Jordan classes are smooth and that their closure is a union of Jordan classes. We parametrize Jordan classes and G_0-orbits in a given class in terms of the action of subgroups of Vinberg's little Weyl group, and include several examples and counterexamples underlying the differences with the symmetric case and the critical issues arising in the theta-situation.Comment: v2: final version to appear in Transform. Group

Entangling Data while Entangling Disciplines. Discussing the Future of Anthropological Collaborations with Data Scientists

This special issue discusses forms of possible collaboration and mutual intermixing between anthropology and data science, by presenting projects and creative experiments that have been conducted astray the two fields. While we may say that all scientists work with data, this special issue focuses on data that are collected and/or processed by digital means. In addition, attention will be paid to computation as anthropologists have recently turned to the study of data, AI and algorithms, offering critical insights about their production and implementation. They have addressed the effects of algorithmic automation (e.g. increasing surveillance, inequality exacerbation, new forms of discrimination) and conducted fieldwork among data scientists in order to bring the socio- cultural dimensions of their work to the forefront. In this introduction, we will illustrate what motivated this special issue and will introduce the articles by positioning them critically within the current debate about computation, big data and AI

Treating eating disorders in groups: A pilot study on the role of a structured intervention on perfectionism on group climate

AbstractSeveral studies have shown the efficacy of group treatments for patients with eating disorders (EDs) who have negative attitudes towards their bodies, also using the group climate as an indicator of process. Within this field of study, perfectionism has been examined as a factor that maintains eating disorders. This study proposes to comprehend what kind of treatment favours a better group climate, by providing a within‐person comparison between two short group treatments of ED patients, where one was not focused on a specific topic and the other was structured around the topic of clinical perfectionism. Two groups of young adult patients with eating disorders were monitored for three months. Group climate was measured both with the Group Climate Questionnaire, which was administered at the end of each session, and through the clinical accounts written by an observer. The findings revealed that the perfectionism group, in comparison with the control group, presented a significantly higher level of engagement and avoidance, along with a lower level of conflict. In particular, the engagement of the perfectionism group increased in accordance with the therapeutic process, whilst in the control group, it remained relatively constant. The conflict decreased in both groups whilst avoidance increased alongside the sessions of the perfectionism group and decreased in the control group. The group on perfectionism, despite its enhanced high levels of avoidance, was effective in promoting a positive group climate. The clinical implications of structured group treatment for eating disorders, which manage the theme of mind‐body splitting, will be discussed

Universal filtered quantizations of nilpotent Slodowy slices

Every conic symplectic singularity admits a universal Poisson deformation and a universal filtered quantization, thanks to the work of Losev and Namikawa. We begin this paper by showing that every such variety admits a universal equivariant Poisson deformation and universal equivariant quantization with respect to any group acting on it by $\mathbb{C}^\times$-equivariant Poisson automorphisms. We go on to study these definitions in the context of nilpotent Slodowy slices. First we give a complete description of the cases in which the finite $W$-algebra is the universal filtered quantization of the slice, building on the work of Lehn--Namikawa--Sorger. This leads to a near-complete classification of the filtered quantizations of nilpotent Slodowy slices. The subregular slices in non-simply-laced Lie algebras are especially interesting: with some minor restrictions on Dynkin type we prove that the finite $W$-algebra is the universal equivariant quantization with respect to the Dynkin automorphisms coming from the unfolding of the Dynkin diagram. This can be seen as a non-commutative analogue of Slodowy's theorem. Finally we apply this result to give a presentation of the subregular finite $W$-algebra in type B as a quotient of a shifted Yangian.Comment: 20 pages, v2: typos corrected in the final section, v3: Proposition 2.17 adde