Speaker：冯仁杰（北京大学）

Time：2月15日 2:00-3:00pm

Room：1518

Title：Critical radius and supremum of random spherical harmonics

Abstract：We first consider deterministic immersions of the d-dimensional sphere into high dimensional Euclidean spaces, where the immersion is via spherical harmonics of level n. The main result of the article is the, a priori unexpected, fact that there is a uniform lower bound to the critical radius of the immersions as n→∞. This fact has immediate implications for random spherical harmonics with fixed L2-norm. In particular, it leads to an exact and explicit formulae for the tail probability of their (large deviation) suprema by the tube formula, and also relates this to the expected Euler characteristic of their upper level sets.