One Arithmetic Gadget, Two Problems

Abstract

There is an absolute constant $c>0$ such that, for every $0<\epsilon \le 1$, arbitrarily large finite sets $A\subset \mathbb{C}$ satisfy \[ |A+A|\leq |A|^{1+\varepsilon},\qquad |AA|\leq |A|^{2-c\varepsilon},\qquad ν_1(A)\geq |A|^{1+c\varepsilon}, \] where ${\nu }_1(A)$ counts unordered unit-distance pairs. We combine the arithmetic directions from the recent unit-distance construction with the multiplicative enlargement used in the recent sum-product construction. The arithmetic ingredients are stated as explicit inputs.