{ "id": "2204.13541", "version": "v1", "published": "2022-04-28T14:44:27.000Z", "updated": "2022-04-28T14:44:27.000Z", "title": "On the Balog-Ruzsa Theorem in short intervals", "authors": [ "Yu-Chen Sun" ], "categories": [ "math.NT", "math.CA", "math.CO" ], "abstract": "In this paper we give a short interval version of the Balog-Ruzsa theorem concerning bounds for the $L_1$ norm of the exponential sum over $r$-free numbers. As an application, we give a lower bound for the $L_1$ norm of the exponential sum defined with the M\\\"obius function. Namely we show that $$\\int_{{\\mathbb T}} \\left|\\sum_{|n-N|