Generalized planning: Non-deterministic abstractions and trajectory constraints

We study the characterization and computation of general policies for families of problems that share a structure characterized by a common reduction into a single abstract problem. Policies mu that solve the abstract problem P have been shown to solve all problems Q that reduce to P provided that mu terminates in Q. In this work, we shed light on why this termination condition is needed and how it can be removed. The key observation is that the abstract problem P captures the common structure among the concrete problems Q that is local (Markovian) but misses common structure that is global. We show how such global structure can be captured by means of trajectory constraints that in many cases can be expressed as LTL formulas, thus reducing generalized planning to LTL synthesis. Moreover, for a broad class of problems that involve integer variables that can be increased or decreased, trajectory constraints can be compiled away, reducing generalized planning to fully observable nondeterministic planning

Mesoscopic non-equilibrium thermodynamics approach to the dynamics of polymers

We present a general formalism able to derive the kinetic equations of polymer dynamics. It is based on the application of nonequilibrium thermodynamics to analyze the irreversible processes taking place in the conformational space of the macromolecules. The Smoluchowski equation results from the analysis of the underlying diffusion process in that space within the scheme of nonequilibrium thermodynamics. We apply the method to different situations, concerning flexible, semiflexible and rod-like polymers and to the case of more concentrated solutions in which interactions become important.Comment: 13 pages (RevTex). To be published in Physica

Digital Resilience: Harnessing the Power of the Collective for Language Preservation. A Success Story for Catalan

El creixement generalitzat de la intel·ligència artificial (IA) ha fet que les tecnologies de la llengua siguin més accessibles que mai i ha portat aquesta tecnologia a la nostra vida diària. Tanmateix, el desenvolupament accelerat de la tecnologia lingüística comporta intrínsecament un biaix cap a una perspectiva anglocèntrica i eurocèntrica, que té com a resultat una representació i un reconeixement limitats de les llengües minoritzades. És ben sabut que la presència d’una llengua en línia en garanteix la supervivència. En aquest article explorem la història d’èxit del català, una llengua minoritzada amb una comunitat activa en línia, que ha establert les bases per al desenvolupament de les tecnologies de la llengua. La història d’èxit de la comunitat catalanoparlant demostra que les comunitats poden tenir un paper important en la supervivència i en l’evolució de les llengües minoritzades en l’era digital.The widespread growth of Artificial Intelligence (AI) has made language technology more accessible than ever before, bringing language technology into our daily lives. Nevertheless, the rapid development of language technology intrinsically carries a bias towards Anglo-centric and Euro-centric perspectives, leading to limited representation and recognition for minoritized languages. It is a fact that the online presence of a language ensures its survival. This article explores the success story of Catalan, a minoritized language with an active online community, which has laid the foundations for language technology development. The Catalan-speaking community’s success story demonstrates how communities can play a significant role in the survival and evolution of minoritized languages in the digital age

The F-threshold of radical ideals

Les F-singularitats són singularitats d'anells commutatius de característica primera relacionats amb l'endomorfisme de Frobenius. Per a poder-les estudiar, s'han introduit invariants numèrics com la multiplicitat de Hilbert-Kunz o la F-signatura, que ofereixen una mesura de com de singular és un anell des del punt de vista de l'aplicació de Frobenius. En aquest treball, introduïm alguns conceptes sobre els mètodes de característica p i calculem el valor d'un d'aquests invariants, els F-llindars, per ideals radicals en un context regular.Las F-singularidades son singularidades de anillos commutativos de característica prima relacionados con el endomorfismo de Frobenius. Para poder estudiarlas, se han introducido invariantes numéricos como la multiplicidad de Hilbert-Kunz y la F-signatura, que ofrecen una medida de cómo de singular es un anillo desde el punto de vista de la aplicación de Frobenius. En este trabajo, introducimos algunos conceptos sobre métodos en característica p y calculamos el valor de uno de estos invariantes, los F-umbrales, en el caso de ideales radicales en un contexto regular.F-singularities are singularities of commutative rings of prime characteristic which are related to the Frobenius endomorphism. In order to study them, researchers have introduced numerical invariants such as the Hilbert-Kunz multiplicity and the F-signature, which provide a measure of how singular a ring is from the point of view of the Frobenius map. In this thesis, we introduce some concepts about characteristic p methods and compute the value of one of these invariants, the F-thresholds, for radical ideals in a regular setting.Outgoin

Influence of Phosphoramidites in Copper-Catalyzed Conjugate Borylation Reaction

Copper(I) has become the preferred metal to catalyze the β-boration of α,β-unsaturated carbonyl compounds, and now we demonstrate that easily accessible monodentate chiral ligands, such as phosphoramidites and phosphites, can be convenient alternative ligands to induce asymmetry in the enantioselective version of this reaction, particularly in the β-boration of α,β-unsaturated imines.

Does losing temporary workers matter? The effects of planned turnover on replacements and unit performance

This study examines the performance consequences of planned turnover. In particular, we investigate the departure of temporary workers due to the expiration of their contracts. We reconcile the contradictory predictions of collective turnover research—that any type of worker’s exit impairs organizational performance—and of contingent work research—that temporary workers’ exits improve organizational performance because they provide flexibility. We argue that the planned turnover of temporary workers has an inverted U shaped relationship with unit performance because it combines flexibility benefits and disruption costs. We also argue that the costs of planned temporary worker turnover are moderated by the proportion and the firm-specific experience of their replacements. We test these arguments using longitudinal monthly data from a leading multinational company in the food and beverage industry, and find support for our hypotheses. The study suggests that managers hiring temporary workers should consider the cost of losing them and challenges the widespread scholarly and managerial assumption that temporary workers are disposable resources