Ergodic behavior of non-conservative semigroups via generalized Doeblin's conditions

Vincent Bansaye (1) , Bertrand Cloez (2) , Pierre Gabriel (3)

1 CMAP - Centre de Mathématiques Appliquées - Ecole Polytechnique
2 MISTEA - Mathématiques, Informatique et STatistique pour l'Environnement et l'Agronomie
3 LMV - Laboratoire de Mathématiques de Versailles

We provide quantitative estimates in total variation distance for positive semi-groups, which can be non-conservative and non-homogeneous. The techniques relies on a family of conservative semigroups that describes a typical particle and Doeblin's type conditions for coupling the associated process. Our aim is to provide quantitative estimates for linear partial differential equations and we develop several applications for population dynamics in varying environment. We start with the asymptotic profile for a growth diffusion model with time and space non-homogeneity. Moreover we provide general estimates for semigroups which become asymptotically homogeneous, which are applied to an age-structured population model. Finally, we obtain a speed of convergence for periodic semi-groups and new bounds in the homogeneous setting. They are are illustrated on the renewal equation.

Mots clés: ergodicity; non-autonomous linear evolution equations; population dynamics; Krein-Rutman theorem; positive semigroups; measure solutions; Floquet theory

Domaines: Equations aux dérivées partielles [math.AP]; Probabilités [math.PR]

Vincent Bansaye, Bertrand Cloez, Pierre Gabriel. Ergodic behavior of non-conservative semigroups via generalized Doeblin's conditions. Acta Applicandae Mathematicae, 2020, 166 (1), pp.29-72. ⟨10.1007/s10440-019-00253-5⟩. ⟨hal-01617071v4⟩