We consider the asymptotic disconnection time of a discrete cylinder (Z/NZ)^d x Z, d>=2 by simple and biased (in the Z direction) random walks. For simple random walk, we derive a sharp asymptotic lower bound that matches the upper bound from [A.-S. Sznitman, Ann. Probab., 2009] which allows us to identify the weak limit of the rescaled disconnection time. For the biased walk, we obtain bounds that asymptotically match in the principal order when the bias is not too strong, which greatly improves results from [D. Windisch, Ann. Appl. Probab., 2008]. Based on a joint work with Yu Liu (PKU) and Yuanzheng Wang (MIT), available at arXiv:2409.17900.

Speaker's Bio: Li Xinyi, Assistant Professor and Researcher at Beijing International Mathematics Research Center, Peking University. I obtained my doctoral degree from the Swiss Federal Institute of Technology in Zurich in 2016, under the guidance of Professor Alain Sol Sznitnam. His research interests mainly focus on probability theory, random fractals, and random geometry. Part of the results were published in journals such as Ann Probab, Probab Theory Related Fields, Comm. Math. Phys.