cosine polynomial


Chowla's cosine problem ★★★

Author(s): Chowla

Problem   Let $ A \subseteq {\mathbb N} $ be a set of $ n $ positive integers and set \[m(A) = - \min_x \sum_{a \in A} \cos(ax).\] What is $ m(n) = \min_A m(A) $?

Keywords: circle; cosine polynomial

Syndicate content