The next meeting of the Applied Mathematics Seminar will be held on November 11, 2025 at 2:00 pm in Room 503 of IMI - BAS. A talk on The number of cycles in a random permutation and the number of segregating sites jointly converge to the Brownian sheet will be delivered by Helmut Pitters (Mannheim, Germany). Abstract: Consider a random permutation of {1, …, ⌊nᵗ²⌋} drawn according to the Ewens measure with parameter t₁, and let K(n, t) denote the number of its cycles, where t ≡ (t₁, t₂) ∈ [0, 1]². Next, consider a sample drawn from a large, neutral population of haploid individuals subject to mutation under the infinitely many sites model of Kimura, whose genealogy is governed by Kingman’s coalescent. Let S(n, t) count the number of segregating sites in [...]

The next meeting of the Applied Mathematics Seminar will be held on October 15, 2025 (Wednesday) at 3:00 pm in Room 503 of IMI - BAS. A talk on Stochastic scattering control of Walsh's spider diffusion with optimal diffraction probability measure selected from its own local-time will be delivered by Isaac Ohavi, who is working in fields such as stochastic control, stochastic optimization, and partial differential equations. Abstract: In this talk, we start by giving a short introduction on "classical" stochastic control theory and its connection with second order nonlinear PDE theory. Then, we present Walsh’s spider diffusions living on a star-shaped network, and explain how these processes are at the origin of new problems of stochastic scattering control. A main direction is to focus and understand [...]