Spin Hamiltonian of Hyperkagome Na4Ir3O8

We derive the spin Hamiltonian for the quantum spin liquid Na4Ir3O8, and then estimate the direct and superexchange contributions between near neighbor iridium ions using a tight binding parametrization of the electronic structure. We find a magnitude of the exchange interaction comparable to experiment for a reasonable value of the on-site Coulomb repulsion. For one of the two tight binding parametrizations we have studied, the direct exchange term, which is isotropic, dominates the total exchange. This provides support for those theories proposed to describe this novel quantum spin liquid that assume an isotropic Heisenberg model.Comment: 9 pages, 4 figure

Electronic Structure of Hyperkagome Na4Ir3O8

We investigate the electronic structure of the frustrated magnet Na4Ir3O8 using density functional theory. Due to strong spin-orbit coupling, the hyperkagome lattice is characterized by a half-filled complex of states, making it a cubic iridium analogue of the high temperature superconducting cuprates. The implications of our results for this unique material are discussed.Comment: expanded discussion with extra figures - 6 pages, 10 figure

Overview of cases before the CJEU on European Consumer Contract Law (2008–2013) – Part II

During the last five years the CJEU had to decide on more than 50 preliminary references in the area of consumer contract law. As a consequence there are far more than 100 decisions available which represent the increasingly concrete basis for a European contract law. Particularly striking is the rising number of questions referred to the CJEU by the new Member States. With regard to quantity, two fields stand out: legal conflicts about financial services of all kinds and about passenger rights. Since the CJEU has developed independent dogmatics for some areas of contract law, it might be necessary to rethink legal categories on the national level.Durant les cinq dernières années, la CJUE a dû répondre à plus de 50 questions préjudicielles dans le domaine du droit des contrats de consommation. En conséquence, il y a bien plus de 100 décisions disponibles qui représentent une base concrète croissante pour un droit européen des contrats. L’accroissement du nombre de questions adressées à la CJUE par les nouveaux Etats membres est particulièrement frappant. Quantitativement, deux domaines se distinguent : les conflits juridiques relatifs aux services financiers de toutes sortes et ceux relatifs auxprétations propres dans quelques domaines du droit des contrats, il pourrait être nécessaire de repenser les catégories juridiques au niveau national.In den letzten fünf Jahren hatte der EuGH mehr als 50 Vorlageverfahren zu entscheiden. Per dato liegen damit weit mehr als 100 Entscheidungen vor, die in immer dichterer Form die Grundlagen für ein europäisches Vertragsrecht konkretisieren. Auffällig ist die steigende Zahl von Vorlagen aus den neuen Mitgliedstaaten. In der Sache dominieren in quantitativer Hinsicht zwei Bereiche: rechtliche Auseinandersetzungen um Finanzdienstleistungen jedweder Art und das Passagier- bzw. Reiserecht. Für Teilbereiche des Vertragsrechts entwickelt der EuGH eine eigenständige Dogmatik, die ein Überdenken nationaler rechtlicher Kategorien notwendig macht

Choice Architectures in the Digital Economy: Towards a New Understanding of Digital Vulnerability

In the digital economy, consumer vulnerability is not simply a vantage point from which to assess some consumers’ lack of ability to activate their awareness of persuasion. Instead, digital vulnerability describes a universal state of defencelessness and susceptibility to (the exploitation of) power imbalances that are the result of the increasing automation of commerce, datafied consumer–seller relations, and the very architecture of digital marketplaces. Digital vulnerability, we argue, is architectural, relational, and data-driven. Based on our concept of digital vulnerability, we demonstrate how and why using digital technology to render consumers vulnerable is the epitome of an unfair digital commercial practice

Assessing the Cross-Market Generalization Capability of the CLAUDETTE System

We present a study aimed at testing the CLAUDETTE system's ability to generalise the concept of unfairness in consumer contracts across diverse market sectors. The data set includes 142 terms of services grouped in five sub-sets: travel and accommodation, games and entertainment, finance and payments, health and well-being, and the more general others. Preliminary results show that the classifier has satisfying performance on all the sectors

Deep learning for detecting and explaining unfairness in consumer contracts

Consumer contracts often contain unfair clauses, in apparent violation of the relevant legislation. In this paper we present a new methodology for evaluating such clauses in online Terms of Services. We expand a set of tagged documents (terms of service), with a structured corpus where unfair clauses are liked to a knowledge base of rationales for unfairness, and experiment with machine learning methods on this expanded training set. Our experimental study is based on deep neural networks that aim to combine learning and reasoning tasks, one major example being Memory Networks. Preliminary results show that this approach may not only provide reasons and explanations to the user, but also enhance the automated detection of unfair clauses

Digital Fairness for Consumers

The New Digital Fairness (NDF) project is a research and advocacy initiative launched by BEUC with support from the Adessium Foundation, seeking to address the challenges and potential harms caused to consumers, citizens and societies by the use of new technologies and business models in today’s digital economy. The present report arrives in direct succession of the EU Consumer Protection 2.0 (EUCP2.0) project and builds on the conceptual framework developed at that stage of the research, particularly in regard to the disempowerment of consumers due to asymmetries of knowledge and power, new categories of consumer vulnerability caused and aggravated by algorithmic environments as well as omnipresent surveillance and behavioural personalisation. This work takes the analysis further, identifying systemic processes gradually weakening the position of consumers in the digitalised markets. It also shows the way forward, by proposing a regulatory framework that would strengthen and safeguard consumers and provide a digital market that is safe and fair to them by design and by default. The broad applicability and technological neutrality of horizontal consumer law render it a fitting vehicle for protecting the needs and safeguarding the rights of modern-day digital consumers. In the light of the ongoing, EU ‘digital fairness’ fitness check assessment of consumer law, this work proposes specific solutions and recommendations that could form the backbone of EU’s regulatory response to the age of digital asymmetries that should be the Digital Fairness Act. This publication constitutes independent research that was commissioned by BEUC, the European Consumer Organisationpean Consumer Organisatio

Automated detection of unfair clauses in online consumer contracts

Consumer contracts too often present clauses that are potentially unfair to the subscriber. We present an experimental study where machine learning is employed to automatically detect such potentially unfair clauses in online contracts. Results show that the proposed system could provide a valuable tool for lawyers and consumers alike