Forte Shinko (UC Berkeley)
Title: Quantitative dimension growth for hyperfiniteness
Time: Wednesday, 15.07.2026, 14:00.
Place: ELTE, D3-211.
Abstract: A seminal result of Gao and Jackson in the study of Borel equivalence relations states that abelian groups have hyperfinite orbit equivalence relations. The key idea in this proof was isolated by Conley, Jackson, Marks, Seward and Tucker-Drob, who showed that showed that hyperfiniteness is equivalent to the existence of a Borel coarse structure which is locally of finite Borel asymptotic dimension. We state a quantitative relaxation of this condition and highlight its applications to two new situations: subexponential growth (joint with Grebík, Marks and Rozhon) and commuting functions (joint with Naryshkin, Weilacher and Yu).