Le séminaire des doctorants se propose de fournir aux doctorants une occasion de s'ouvrir aux autres domaines des mathématiques que le leur. A chaque séance, un intervenant réalise un exposé sur un fait standard de leur domaine d'étude, de niveau adapté à l'ensemble des doctorants.

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The PhD students seminar aims to provide PhD students with an opportunity to explore other areas of mathematics beyond their own. At each session, a speaker gives a presentation on a standard topic in their field of study, at a level suitable for all doctoral students.

First, I will present the models of Galton-Watson processes and some results in the classical case, in varying environments, and in i.i.d. environments. Then, I will introduce Galton-Watson processes in dynamical environments, establishing connections with the models discussed previously. These processes can be classified into three different regimes: uniformly subcritical, critical and uniformly supercritical. We will study the probability of extinction in the  uniformly supercritical case.