Є Universite catholique de Louvain Є Є Departement des Sciences economiques ` Є Є These presentee en vue de lobtention du grade de Є docteur en sciences economiques Essays on economic dynamics under heterogeneity Anton O. Belyakov Composition du jury: Julio Davila (promoteur) Raouf Boucekkine Carmen Camacho Vladimir Veliov Mathieu Parenti Acknowledgements First of all I would like to thank my supervisors Raouf Boucekkine and Julio Davila. I'm grateful to other members of my doctoral jury: Mathieu Parenti,