Asymptotics of the counting function for resonances

The talk is devoted to the leading term in the asymptotics of the resonances' counting function. It is planned to give a short review of more classical results for Schrödinger operators with sufficiently good potentials and, in more detail, of so-called Weyl-type asymptotics of resonances for quantum graphs and point interactions. The main goal is to show that for point interactions Weyl-type asymptotics is generic. The last result has been obtained jointly with Sergio Albeverio.