On April 6, 2026 (Monday) at 2:15 p.m. in Room 478 of IMI-BAS, a joint meeting of The Seminar on Optimization (PMI) and the Seminar on Operations Research (IMI) will be held. A talk on Hausdorff characterizations of first countable T1 spaces via fixed point theorems will be delivered by Detelina Kamburova. Everybody is invited.