Characterization of an Algerian diatomite by inverse gas chromatography: Specific and non-specific contribution and Lewis acid–base parameters

The fundamental understanding of the behavior of a solid is intimately related to the understanding of the interactions on the surface of the latter, a major challenge in particular if the material is natural and ecological. The infinite dilution-inverse gas chromatography was used to evaluate the surface thermodynamic properties of several phases (grafted and/or coated) diatomite. A series of non- or polar-solute probes were injected at temperatures of 45?°C and 90?°C. The dispersive surface free energies values of the supports decrease with increasing temperature and their active surface is amphoteric with predominantly acidic character.     

Localisation spectrale et sous-espaces hyperinvariants

To get hyperinvariant subspaces, we establish a relation between the growth of the resolvent and the geometry of the spectrum. Our approach is based on a resolution of the generalized Dirichlet problem.

     

On some algorithms for limiting average Markov decision processes

We consider limiting average Markov decision processes (MDP) with finite state and action spaces. We propose some algorithms to determine optimal strategies for deterministic and general MDPs. These algorithms are based on graph theory and the construction of levels in some aggregated MDP.     

Sur le Degré Minimum des Connexions Polynomiales Entre les Projections Dans une Algèbre de Banach

Résumé  L’insiemeP degli elementi idempotenti di un’algebra di BanachA é in generale non connesso. J. Zemanek [7] e B. Aupetit [1] hanno dimostrato che le componenti connesse di tale insieme sono connesse per archi. Inoltre J. Esterle [4] ha dimostrato che due elementi diP appartenti alla stessa componente connessa possono essere collegati attraverso un cammino polinomiale. In questo lavoro si studia il minimo grado di tali polinomi seA è un’algebra di Banach di dimensione finita oppure seA è l’algebra degli operatori limitati su uno spazio di Banach.     

Hierarchical algorithms for discounted and weighted Markov decision processes

We consider a discrete time finite Markov decision process (MDP) with the discounted and weighted reward optimality criteria. In [1] the authors considered some decomposition of limiting average MDPs. In this paper, we use an analogous approach for discounted and weighted MDPs. Then, we construct some hierarchical decomposition algorithms for both discounted and weighted MDPs.     

Bounded Local Resolvents for Operators with Single-Valued Extension Property

Let T be a bounded operator with (SVEP) on its localizable spectrum \(\sigma _\mathrm{loc}(T)\). We show that for every open subset U of \(\sigma _\mathrm{loc}(T)\), there exists a unit vector x whose local spectrum coincides with the closure of U, and such that its local resolvent function is bounded. This result answers positively to an open question stated by several authors, and extends the both cases of operators with trivial divisible subspace and operators whose point spectrum has empty interior.