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Propositional incompleteness, the one and thousands nights of organizing
No full textInternational audiencePresentation at the Academy of Management (AoM) Symposium entitled "Bracketing Process? Event as Action but Also Non-Action". Proposition of a processual approach based on Whitehead's view of the generative incompleteness of events, crossed with the narrative and history of the Thousands and One Nights
Legal Form or Unfair Substance? A Symposium Around the Controlled Foreign Company (CFC) Rule
No full textInternational audienceThis symposium around the case of the Controlled Foreign Company (CFC) rule offers to CONVIVIUM readers a debate which saw both authors stalling in their respective positions. On the one side, the negative taxation principle under which ‘tax avoidance is acceptable under the law;’ on the other side, the positive taxation principle that ‘all and every citizens shall pay a fair share of taxation.’ Their discussion certainly raises important matters for the current state of affairs in tax law and regulation, but it does not provide any explicit solution for issues which were raised. In this context, readers may aim at learning from both authors
Peierls bounds from random Toom contours
No full textFor deterministic monotone cellular automata on the d-dimensional integer lattice, Toom (1980) has given necessary and sufficient conditions for the all-one fixed point to be stable against small random perturbations. We are interested in the open problem of extending Toom's result to monotone cellular automata with intrinsic randomness, where the unperturbed evolution is random with i.i.d. update rules attached to the space-time points. For some applications it is also desirable to consider a more general graph structure, so we assume that the underlying lattice is an arbitrary countable group. Toom's proof of stability is based on a Peierls argument. In previous work, we demonstrated that this Peierls argument can also be used to prove stability for cellular automata with intrinsic randomness, but in this case estimating the Peierls sum becomes much harder than in the deterministic case. In the present paper, we develop a method based on random contours to estimate the Peierls sum and apply it to prove new stability results for monotone cellular automata with intrisic randomness. We also demonstrate the limitations of the method by constructing an example where the Peierls sum is infinite for arbitrary small perturbations even though stability is believed to hold.</div
THERMAL BOUNDARY CONDITIONS IN FRACTIONAL SUPERDIFFUSION OF ENERGY
No full textWe study heat conduction in a one-dimensional finite, unpinned chain of atoms perturbed by stochastic momentum exchange and coupled to Langevin heat baths at possibly distinct temperatures placed at the endpoints of the chain. While infinite systems without boundaries are known to exhibit superdiffusive energy transport described by a fractional heat equation with the generator -|∆| 3/4 , the corresponding boundary conditions induced by heat baths remain less understood. We establish the hydrodynamic limit for a finite chain with n + 1 atoms connected to thermostats at the endpoints, deriving the macroscopic evolution of the averaged energy profile. The limiting equation is governed by a non-local Lévy-type operator, with boundary terms determined by explicit interaction kernels that encode absorption, reflection, and transmission of long-wavelength phonons at the baths. Our results provide the first rigorous identification of boundary conditions for fractional superdiffusion arising directly from microscopic dynamics, highlighting their distinction from both diffusive and pinned-chain settings.</div
Flat Standing Sphere Blow-up Solutions for the Nonlinear Heat Equation
No full textIn this paper, we prove the existence of a singular standing sphere blow-up solution for the nonlinear heat equation with radial symmetry. This solution develops a finite-time singularity on a fixed-radius sphere and exhibits a flat blow-up profile. Our construction refines the method developed by Merle and Zaag \cite{MZJEMS24} which reduces the infinite-dimensional dynamics to a finite-dimensional problem in radial case. The solution satisfies explicit asymptotics near the singular ring and remains regular elsewhere
Revealing POMDPs: Qualitative and Quantitative Analysis for Parity Objectives
No full textInternational audiencePartially observable Markov decision processes (POMDPs) are a central model for uncertainty in sequential decision making. The most basic objective is the reachability objective, where a target set must be eventually visited, and the more general parity objectives can model all ω-regular specifications. For such objectives, the computational analysis problems are the following: (a) qualitative analysis that asks whether the objective can be satisfied with probability 1 (almost-sure winning) or probability arbitrarily close to 1 (limit-sure winning); and (b) quantitative analysis that asks for the approximation of the optimal probability of satisfying the objective. For general POMDPs, almost-sure analysis for reachability objectives is EXPTIME-complete, but limit-sure and quantitative analyses for reachability objectives are undecidable; almost-sure, limit-sure, and quantitative analyses for parity objectives are all undecidable. A special class of POMDPs, called revealing POMDPs, has been studied recently in several works, and for this subclass the almost-sure analysis for parity objectives was shown to be EXPTIME-complete. In this work, we show that for revealing POMDPs the limit-sure analysis for parity objectives is EXPTIME-complete, and even the quantitative analysis for parity objectives can be achieved in EXPTIME.formation of the state. POMDPs generalize classic models: Markov decision processes (MDPs), in which the state is fully observed (Puterman 2014), and blind MDPs, in which no state information is observed and are equivalent to Probabilistic Finite Automata (Rabin 1963; Paz 1971).Objectives The controller aims to maximize an objective function, which formally captures the desired behaviors of</div
Le travail féministe : le militantisme au Planning familial à l’épreuve de sa professionnalisation Rennes, Presses universitaires de Rennes, coll. « Archives du féminisme », 2022, 256 pages
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DeepInverse: A Python package for solving imaging inverse problems with deep learning
No full textInternational audienceDeepInverse is an open-source PyTorch-based library for imaging inverse problems. DeepInverse implements all steps for image reconstruction, including efficient forward operators, defining and solving variational problems and designing and training advanced neural networks, for a wide set of domains (medical imaging, astronomical imaging, remote sensing, computational photography, compressed sensing and more)
Cycles of inequality in the marketplace: insights from macro, marketer, and consumer perspectives
No full textSeeking inequality via differentiation is a fundamental theme in the marketing literature: consumers derive utility from products that convey socially valued attributes, and marketers target consumers by giving them opportunities to differentiate on socially valued attributes. However, as a large body of evidence shows, inequality can reduce consumer well-being and limit economic growth. In this paper, we take a systemic view of marketplace inequality, examining the interdependence among consumers, marketers, and macro forces in shaping inequality in markets for goods and services. Our broad review of the marketing literature across ten marketing journals and a variety of subdomains within the field (e.g., macromarketing, consumer behavior, marketing strategy, quantitative marketing) suggests that macro forces, marketers, and consumers are all part of a dynamic system in which each contributes to creating, perpetuating, and disrupting cycles of marketplace inequality. By highlighting the process by which inequality can be created, perpetuated, and reduced, we hope to give marketing researchers and practitioners insight into interventions that have the potential to increase consumer well-being and marketer profitability