L’année 2024 est marquée à la fois par la passivité de la pratique conventionnelle du Canada et l’hyperactivité de sa pratique contentieuse. L’apurement de l’arriéré des réclamations fondées sur le régime de règlement des différends entre investisseurs et États (RDIE) de l’Accord de libre-échange nord-américain entre le gouvernement du Canada, le gouvernement des États-Unis et le gouvernement du Mexique (ALÉNA) se poursuit.1 De nombreuses sentences sont aussi rendues dans des affaires portées par des investisseurs canadiens à l’étranger, des sociétés minières pour l’essentiel. Ces affaires permettent de tester les innovations juridiques visant à renforcer le droit de légiférer de l’État dans les traités plus récents du Canada. Une première sentence très attendue sur la question hautement controversée de la portée temporelle du régime transitoire de RDIE de l’Accord entre le Canada, les États-Unis et le Mexique (ACÉUM)2 est rendue dans l’affaire TC Energy et TransCanada c États-Unis (II)3 et se solde en faveur de l’État. La controverse sur la portée temporelle de ce régime transitoire fait l’objet d’une analyse détaillée dans la chronique cette année. Un tour d’horizon des principaux autres faits marquants de 2024 est d’abord effectué en ce qui concerne la pratique conventionnelle et la pratique contentieuse du Canada.

Since the setting for Antoninus Liberalis, Metamorphoses 4 has been misinterpreted by commentators and historians, a review of the evidence for the toponym Dryopis is warranted. The narrative logic of the account demands that it be set in Ambracia, but most have interpreted Dryopis as the area near Mt Oeta. A close review of the first lines show that Antoninus’ account is indeed set in Ambracia, which was also called Dryopis.

We consider two-person zero-sum semi-Markov games with incomplete reward information on one side under the expected discount criterion. First, we prove that the value function exists and satisfies the Shapley equation. From the Shapley equation, we construct an optimal policy for the informed player. Second, to show the existence of an optimal policy for the uninformed player, we introduce an auxiliary dual game and establish the relationship between the primal game and the dual game. By this relationship, we also prove the existence of the value function of the dual game, and then construct an optimal policy for the uninformed player in the primal game. Finally, we develop two iterative algorithms to compute $\varepsilon$-optimal policies for the informed player and the uninformed player, respectively.

A random variable $\xi$ has a light-tailed distribution (for short, is light-tailed) if it possesses a finite exponential moment, ${\mathbb{E}} \, {\exp}{(\lambda \xi)} <\infty$ for some $\lambda >0$, and has a heavy-tailed distribution (is heavy-tailed) if ${\mathbb{E}} \, {\exp}{(\lambda\xi)} = \infty$ for all $\lambda>0$. Leipus et al. (2023 AIMS Math. 8, 13066–13072) presented a particular example of a light-tailed random variable that is the minimum of two independent heavy-tailed random variables. We show that this phenomenon is universal: any light-tailed random variable with right-unbounded support may be represented as the minimum of two independent heavy-tailed random variables. Moreover, a more general fact holds: these two independent random variables may have as heavy-tailed distributions as we wish. Further, we extend the latter result to the minimum of any finite number of independent random variables. We also comment on possible generalizations of our result to the case of dependent random variables.

Recent palaeobiological studies have emphasized the need for interpretations of the fossil record to consider spatial changes in environmental conditions (e.g. topography, climate). Establishing the role the environment plays in determining the distributions of extinct and existing organisms is complicated by biological evolution. Using available observations to ‘see through’ the randomness of biological evolution to determine contributions from environmental change is not trivial because of the sparsity of the fossil record, lack of precise information about rates of evolution, and because we obviously cannot physically re-run the evolutionary history that resulted in modern biodiversity or the fossil record. To address these issues, we establish scales and scenarios in which spatial environmental change is manifested in records of the number of species in a given area (richness) generated by eco-evolutionary simulation. Evolutionary processes that are likely to be random on the timescales of environmental change are included. Signals of environmental change that are likely to be hidden by the effects of ‘noisy’ evolutionary processes and those likely to emerge are identified. The ‘experiment of life’ is simulated many times, producing statistical insights. Results show that the spatial rate of environmental change is strongly correlated with species richness when the ability of organisms to disperse is high. Interaction between scale, dispersal and environmental structure is shown to determine both statistical and spatial distributions of richness. As a proof-of-concept, we compare predictions to bird species richness. The results emphasize the need to consider the randomness of evolution when interpreting the observations of extinct or present life on Earth.

It is a privilege to write a preface to this Symposium on Canada before International Courts and Tribunals, which includes many stimulating and insightful contributions. In this preface, I go back to the beginning and focus on Canada’s first cases at the International Court of Justice (ICJ) and before international arbitral tribunals.