Perturbations of Positive Semigroups and Applications to Population Genetics.
Piecewise atone interpolation of monotone operators
Poincaré inequalities and hitting times
Equivalence of the spectral gap, exponential integrability of hitting times and Lyapunov conditions is well known. We give here the correspondence (with quantitative results) for reversible diffusion processes. As a consequence, we generalize results of Bobkov in the one dimensional case on the value of the Poincaré constant for log-concave measures to superlinear potentials. Finally, we study various functional inequalities under different hitting times integrability conditions (polynomial,…)....
Poincaré inequality for some measures in Hilbert spaces and application to spectral gap for transition semigroups
Point interactions in Lp .
Poisson's equation and characterizations of reflexivity of Banach spaces
Let X be a Banach space with a basis. We prove that X is reflexive if and only if every power-bounded linear operator T satisfies Browder’s equality = (I-T)XWe then deduce that X (with a basis) is reflexive if and only if every strongly continuous bounded semigroup with generator A satisfies . The range (I-T)X (respectively, AX for continuous time) is the space of x ∈ X for which Poisson’s equation (I-T)y = x (Ay = x in continuous time) has a solution y ∈ X; the above equalities for the ranges...
Positive C...-semigroups on C*-algebras.
Positivity and stability for a system of transport equations with unbounded boundary perturbations.
Positivity in the theory of supercyclic operators
A bounded linear operator T defined on a Banach space X is said to be supercyclic if there exists a vector x ∈ X such that the projective orbit {λTⁿx : λ ∈ ℂ, n ∈ ℕ} is dense in X. The aim of this survey is to show the relationship between positivity and supercyclicity. This relationship comes from the so called Positive Supercyclicity Theorem. Throughout this exposition, interesting new directions and open problems will appear.
Potential-theoretical methods in the construction of measure-valued Markov branching processes
We develop potential-theoretical methods in the construction of measure-valued branching processes.We complete results of P. J. Fitzsimmons and E. B. Dynkin on the construction, regularity and other properties of the superprocess associated with a given right process and a branching mechanism.
Power-bounded elements and radical Banach algebras
Firstly, we give extensions of results of Gelfand, Esterle and Katznelson--Tzafriri on power-bounded operators. Secondly, some results and questions relating to power-bounded elements in the unitization of a commutative radical Banach algebra are discussed.
Precise estimates on the rate at which certain diffusions tend to equilibrium.
Precompactness in the uniform ergodic theory
We characterize the Banach space operators T whose arithmetic means form a precompact set in the operator norm topology. This occurs if and only if the sequence is precompact and the point 1 is at most a simple pole of the resolvent of T. Equivalent geometric conditions are also obtained.
Probabilistic representations of operator semigroups - A unifying approach.
Product integrals in strongly differentiate power associative groupoids.
Propriétés d'invariance du domaine du générateur infinitésimal étendu d'un processus de Markov
Pseudo almost periodic and automorphic mild solutions to nonautonomous neutral partial evolution equations
In this work, we present a new concept of Stepanov weighted pseudo almost periodic and automorphic functions which is more generale than the classical one, and we obtain a new existence result of μ-pseudo almost periodic and μ-pseudo almost automorphic mild solutions for some nonautonomous evolution equations with Stepanov μ-pseudo almost periodic terms. An example is shown to illustrate our results.
Pseudo differential operators with negative definite symbols of variable order.
One way to represent the generator of a Markov process is given by pseudo differential operators. Above all this is due to the fact that the generator satisfies the so-called positive maximum principle (...).
Pseudotopologies with applications to one-parameter groups, von Neumann algebras, and Lie algebra representations
For any pair E,F of pseudotopological vector spaces, we endow the space L(E,F) of all continuous linear operators from E into F with a pseudotopology such that, if G is a pseudotopological space, then the mapping L(E,F) × L(F,G) ∋ (f,g) → gf ∈ L(E,G) is continuous. We use this pseudotopology to establish a result about differentiability of certain operator-valued functions related with strongly continuous one-parameter semigroups in Banach spaces, to characterize von Neumann algebras, and to establish...
Puissances d'un opérateur régularisant