The communication complexity of non-signaling distributions

We study a model of communication complexity that encompasses many well-studied problems, including classical and quantum communication complexity, the complexity of simulating distributions arising from bipartite measurements of shared quantum states, and XOR games. In this model, Alice gets an input x, Bob gets an input y, and their goal is to each produce an output a,b distributed according to some pre-specified joint distribution p(a,b|x,y). We introduce a new technique based on affine combinations of lower-complexity distributions. Specifically, we introduce two complexity measures, one which gives lower bounds on classical communication, and one for quantum communication. These measures can be expressed as convex optimization problems. We show that the dual formulations have a striking interpretation, since they coincide with maximum violations of Bell and Tsirelson inequalities. The dual expressions are closely related to the winning probability of XOR games. These lower bounds subsume many known communication complexity lower bound methods, most notably the recent lower bounds of Linial and Shraibman for the special case of Boolean functions. We show that the gap between the quantum and classical lower bounds is at most linear in the size of the support of the distribution, and does not depend on the size of the inputs. This translates into a bound on the gap between maximal Bell and Tsirelson inequality violations, which was previously known only for the case of distributions with Boolean outcomes and uniform marginals. Finally, we give an exponential upper bound on quantum and classical communication complexity in the simultaneous messages model, for any non-signaling distribution. One consequence is a simple proof that any quantum distribution can be approximated with a constant number of bits of communication.Comment: 23 pages. V2: major modifications, extensions and additions compared to V1. V3 (21 pages): proofs have been updated and simplified, particularly Theorem 10 and Theorem 22. V4 (23 pages): Section 3.1 has been rewritten (in particular Lemma 10 and its proof), and various minor modifications have been made. V5 (24 pages): various modifications in the presentatio

Co-designing transformation research : lessons learned from research on deliberate practices for transformation

Co-production of new knowledge can enhance open and integrative research processes across the social and natural sciences and across research/science, practice and policy interrelationships. Thus, co-production is important in the conduct of research about and for transformations to sustainability. While co-design is an integral part of co-production, it often receives limited attention in the conduct of co-produced research. This paper reports on lessons learned from an early stage of the co-design process to develop research on deliberate practices for transformative change. Key lessons learned are the need to: (1) ensure co-design processes are themselves carefully designed; (2) encourage emergence of new ways of thinking about problem formulation through co-design; (3) carefully balance risks for the participants involved while also enhancing opportunities for intellectual risk taking; (4) facilitate personal transformations in co-design as a way to stimulate and encourage further creativity; and (5) for funders to carefully and constructively align criteria or incentives through which a project or future proposal will be judged to the goals of the co-design, including for instrumental outcomes and objectives for creativity and imagination. Given that co-design necessarily involves a reflective practice to iteratively guide emergence of new thinking about the practices of change, co-design can itself be considered an important deliberate practice for transforming the conduct of research and the contribution of that research to social transformations

Von implizitem Know-how zu expliziten Thesen: inter- und transdisziplinärer Wissensaustausch

Um komplexe gesellschaftliche Probleme lösen zu können, sollte relevantes Wissen aus allen Bereichen genutzt werden. Welche Methoden eignen sich, um den Austausch von Wissen zwischen verschiedenen Akteursgruppen aus unterschiedlichen Wissenssystemen zu ermöglichen? Die AG Wissensaustausch der SAGUF (Schweizerische Akademische Gesellschaft für Umweltforschung und Ökologie) begibt sich auf die Suche nach Erfolgsfaktoren für den Wissensaustausch

Impacts of Globalization Processes on the Swiss National Business Elite Community : A Diachronic Analysis of Swiss Large Corporations (1980-2010)

This paper investigates the impacts of globalization processes on the Swiss business elite community during the 1980-2010 period. Switzerland has been characterized in the 20th century by its extraordinary stability and by the strong cohesion of its elite community. To study recent changes, we focus on Switzerland's 110 largest firms' by adopting a diachronic perspective based on three elite cohorts (1980, 2000, and 2010). An analysis of interlocking directorates allows us to describe the decline of the Swiss corporate network. The second analysis focuses on top managers' profiles in terms of education, nationality as well as participation in national community networks that used to reinforce the cultural cohesion of the Swiss elite community, especially the militia army. Our results highlight a slow but profound transformation of top management profiles, characterized by a decline of traditional national elements of legitimacy and the emergence of new "global" elements. The diachronic and combined analysis brings into light the strong cultural changes experienced by the national business elite community