Bargaining over a climate deal: deadline and delay

Assuming that a North-South transfer is the key to effective climate cooperation, we ask when and how much the North should offer to the South in return for a commitment to reduce deforestation and forest degradation. In light of the risk of irreversible damage over time, we examine a negotiation with a deadline. In this case, the North threatens the South over a negotiation dead-end in case an agreement is not reached rapidly. We assess the conditions for an agreement to be immediate or delayed, and discuss those situations likely to result in negotiation failure. Despite the risk of irreversible damage over time, we show that cooperation is likely to be delayed and we identify situations wherein the North and South do not reach an agreement within the deadline. Although Pareto-improving, cooperation may collapse because of inefficiencies related to incomplete information. What’s more, we show that in negotiations with a deadline, uncertainty about the benefits deriving from cooperation and the irreversibility of the damage that will be caused if cooperation is delayed are the two key components affecting choice.     

New estimates for the Laplacian,the div–curl,and related Hodge systems

We establish new estimates for the Laplacian, the div–curl system, and more general Hodge systems in arbitrary dimension, with an application to minimizers of the Ginzburg–Landau energy. To cite this article: J. Bourgain, H. Brezis, C. R. Acad. Sci. Paris, Ser. I 338 (2004).     

Semimartingale: Itô or not ?

Itô semimartingales are the semimartingales whose characteristics are absolutely continuous with respect to Lebesgue measure. We study the importance of this assumption for statistical inference on a discretely sampled semimartingale in terms of the identifiability of its characteristics, their estimation, and propose tests of the Itô property against the non-Itô alternative when the observed semimartingale is continuous, or discontinuous with finite activity jumps, and under a number of technical assumptions.     

Unbalanced optimal transport: Dynamic and Kantorovich formulations

This article presents a new class of distances between arbitrary nonnegative Radon measures inspired by optimal transport. These distances are defined by two equivalent alternative formulations: (i) a dynamic formulation defining the distance as a geodesic distance over the space of measures (ii) a static “Kantorovich” formulation where the distance is the minimum of an optimization problem over pairs of couplings describing the transfer (transport, creation and destruction) of mass between two measures. Both formulations are convex optimization problems, and the ability to switch from one to the other depending on the targeted application is a crucial property of our models. Of particular interest is the Wasserstein–Fisher–Rao metric recently introduced independently by [7], [15]. Defined initially through a dynamic formulation, it belongs to this class of metrics and hence automatically benefits from a static Kantorovich formulation.     

Diverse Imprecise Goal Programming Model Formulations

The goal programming (GP) model is probably the best known in mathematical programming with multiple objectives. Available in various versions, GP is one of the most powerful multiple objective methods which has been applied in much varied fields. It has also been the target of many criticisms among which are those related to the difficulty of determining precisely the goal values as well as those concerning the decision-maker's near absence in this modelling process. In this paper, we will use the concept of indifference thresholds for modelling the imprecision related to the goal values. Many classical imprecise and fuzzy GP model formulations can be considered as a particular case of the proposed formulation.     

Comments on two Notes by L. Ma and X. Xu

In this Note I discuss some assertions made by L. Ma and X. Xu (2009) [6] and L. Ma (2010) [5], which need to be corrected and supplemented with additional references.     

Frustrated Lewis Pair Chemistry Enables N2 Borylation by Formal 1,3-Addition of a B−H Bond in the Coordination Sphere of Tungsten

The first example of a formal 1,3-B−H bond addition across the M−N≡N unit of an end-on dinitrogen complex has been achieved. The use of Piers’ borane HB(C₆F₅)₂ was essential to observe this reactivity and it plays a triple role in this transformation: 1) electrophilic N₂-borylation agent, 2) Lewis acid in a frustrated Lewis pair-type B−H bond activation, and 3) hydride shuttle to the metal center. This chemistry is supported by NMR spectroscopy and solid-state characterization of products and intermediates. The combination of chelate effect and strong σ donation in the diphosphine ligand 1,2-bis(diethylphosphino)ethane was mandatory to avoid phosphine dissociation that otherwise led to complexes where borylation of N₂ occurred without hydride transfer.