Quantitative estimates on the sharp threshold of propagation in reaction-diffusion equations

In this talk, we focus on the (sharp) threshold phenomena arising in some reaction-diffusion equations supplemented with some compactly supported initial data. In the so-called ignition and bistable cases, we will present the first sharp quantitative estimate on the (sharp) threshold values. We also give some numerical simulations which allow us to conjecture some refined estimates. Last, if times allows, we will provide related results in the case of a degenerate monostable nonlinearity “not enjoying the hair trigger effect”. This is based on joint work with Matthieu Alfaro, Arnaud Ducrot and Christophe Besse.