{"count":1,"next":null,"previous":null,"results":[{"id":71443,"title":"Mathematics Colloquium","slug":"mathematics-colloquium-13","event_url":"https://memento.epfl.ch/event/mathematics-colloquium-13","visual_url":"https://memento.epfl.ch/image/32790/200x112.jpg","visual_large_url":"https://memento.epfl.ch/image/32790/720x405.jpg","visual_maxsize_url":"https://memento.epfl.ch/image/32790/max-size.jpg","lang":"en","start_date":"2026-06-17","end_date":"2026-06-17","start_time":"16:15:00","end_time":"17:15:00","description":"<strong>Title</strong>: <br>\r\nPositive random walks and positive-semidefinite random matrices<br>\r\n<br>\r\n<strong>Abstract</strong>:<br>\r\nOn the real line, a random walk that can only move in the positive direction is very unlikely to remain close to its origin. After a fixed number of steps, the left tail has a Gaussian profile under minimal assumptions. Remarkably, a similar phenomenon occurs when we consider a positive random walk on the cone of positive-semidefinite matrices. After a fixed number of steps, the minimum eigenvalue is described by a Gaussian random matrix model.<br>\r\nThis talk introduces a new way to make this intuition rigorous. The methodology addresses an open problem in computational mathematics about sparse random embeddings. The presentation targets a general mathematical audience.<br>\r\nPreprint: <a href=\"https://arxiv.org/abs/2501.16578\" target=\"_blank\">https://arxiv.org/abs/2501.16578</a><br>\r\n<br>\r\n<strong>Please register on the following form : </strong>https://forms.gle/ppXwKo9HmTgFk3rc7","image_description":"","creation_date":"2026-04-01T11:03:30","last_modification_date":"2026-04-01T11:03:45","link_label":"","link_url":"","canceled":"False","cancel_reason":"","place_and_room":"BCH 2201","url_place_and_room":"https://plan.epfl.ch/?room==BCH%202201","url_online_room":"","spoken_languages":["https://memento.epfl.ch/api/v1/spoken_languages/2/?format=json"],"speaker":"Prof. Joel A. Tropp, Steele Family Professor of Applied &amp; Computational Mathematics, Caltech","organizer":"Prof. Nicolas Boumal","contact":"Institute of Mathematics","is_internal":"True","theme":"","vulgarization":{"id":2,"fr_label":"Public averti","en_label":"Informed public"},"registration":{"id":2,"fr_label":"Sur invitation","en_label":"Invitation required"},"keywords":"","file":null,"icalendar_url":"https://memento.epfl.ch/event/export/120257/","category":{"id":1,"code":"CONF","fr_label":"Conférences - Séminaires","en_label":"Conferences - Seminars","activated":true},"academic_calendar_category":null,"domains":[],"mementos":["https://memento.epfl.ch/api/v1/mementos/402/?format=json","https://memento.epfl.ch/api/v1/mementos/5/?format=json","https://memento.epfl.ch/api/v1/mementos/7/?format=json"]}]}