Not hot enough: cooling-off periods and the recent developments under the Energy Charter Treaty

Cooling-off provisions in international investment agreements guarantee that investors and host States resolve their disputes in the most efficient manner. Aimed at offering the parties the opportunity to amicably settle their differences, cooling-off provisions remain a controversial issue in the jurisprudence on international arbitral tribunals. Arbitral tribunals are still split between considering the cooling-off provision as a procedural requirement or as an admissibility or jurisdictional requirement. Each of these positions triggers different practical consequences, with serious outcomes for the arbitral process.This note addresses the latest developments concerning the cooling-off provision under one international investment agreement–the Energy Charter Treaty

Some Remarks on the Model Theory of Epistemic Plausibility Models

Classical logics of knowledge and belief are usually interpreted on Kripke models, for which a mathematically well-developed model theory is available. However, such models are inadequate to capture dynamic phenomena. Therefore, epistemic plausibility models have been introduced. Because these are much richer structures than Kripke models, they do not straightforwardly inherit the model-theoretical results of modal logic. Therefore, while epistemic plausibility structures are well-suited for modeling purposes, an extensive investigation of their model theory has been lacking so far. The aim of the present paper is to fill exactly this gap, by initiating a systematic exploration of the model theory of epistemic plausibility models. Like in 'ordinary' modal logic, the focus will be on the notion of bisimulation. We define various notions of bisimulations (parametrized by a language L) and show that L-bisimilarity implies L-equivalence. We prove a Hennesy-Milner type result, and also two undefinability results. However, our main point is a negative one, viz. that bisimulations cannot straightforwardly be generalized to epistemic plausibility models if conditional belief is taken into account. We present two ways of coping with this issue: (i) adding a modality to the language, and (ii) putting extra constraints on the models. Finally, we make some remarks about the interaction between bisimulation and dynamic model changes.Comment: 19 pages, 3 figure

Automated Verification of Quantum Protocols using MCMAS

We present a methodology for the automated verification of quantum protocols using MCMAS, a symbolic model checker for multi-agent systems The method is based on the logical framework developed by D'Hondt and Panangaden for investigating epistemic and temporal properties, built on the model for Distributed Measurement-based Quantum Computation (DMC), an extension of the Measurement Calculus to distributed quantum systems. We describe the translation map from DMC to interpreted systems, the typical formalism for reasoning about time and knowledge in multi-agent systems. Then, we introduce dmc2ispl, a compiler into the input language of the MCMAS model checker. We demonstrate the technique by verifying the Quantum Teleportation Protocol, and discuss the performance of the tool.Comment: In Proceedings QAPL 2012, arXiv:1207.055

A Logic for Coalgebraic Simulation

AbstractBuilding on the work of L. Moss on coalgebraic logic, we study in a general setting a class of infinitary modal logics for F-coalgebras, designed to capture simulation and bisimulation. We use work by A. Thijs on coalgebraic modelling of simulation, in terms of relators Γ as extensions of functors. We prove our logics can indeed capture simulation and bisimulation, i.e. the existence of a simulation (or bisimulation) is equivalent to the preservation of (or equivalence with respect to) certain classes of sentences. Moreover, we prove that one can characterize any given coalgebra up to simulation (and, in certain conditions, up to bisimulation) by a single sentence. We show that truth for this logic can be understood as a simulation relation itself, but with respect to a richer functor F moreover, it is the the largest simulation, i.e. the similarity relation between states of the coalgebra and elements of the language. This sheds a new perspective on the classical preservation and characterizability results, and also on logic games. The two kinds of games normally used in logic (“truth games” to define the semantics dynamically, and “similarity games” between two structures) are seen to be the same kind of game at the level of coalgebras: simulation games

The on-going violence in Ukraine demonstrates the weakness of EU crisis diplomacy

Despite a ceasefire being announced in Ukraine on 5 September, violence has continued, with the UN High Commissioner for Human Rights announcing on 20 November that an estimated 13 people a day have been killed in fighting since the agreement was reached. Iulian Romanyshyn and Dorina Baltag write on the EU’s overall approach to crisis diplomacy in Ukraine. They argue that despite some limited successes such as the agreement to guarantee Russian gas supplies, it will be necessary for the EU to take a much harder line with Russia if a genuine solution is to be reached