Discretized sum-product type problems: Energy variants and Applications

Abstract: In this paper, we provide estimates for the additive discretized energy of [\sum_{c\in C} |{(a_1, a_2, b_1, b_2)\in A^2\times B^2: |(a_1 +cb_1) - (a_2 + cb_2)|\le \delta}|_{\delta},] that depend on non-concentration conditions of the sets. Our proof follows the Guth-Katz-Zahl approach (2021) with appropriate changes along the way clarifying and optimizing many of the steps. Several applications will also be discussed.