Asymmetric estimates and the sum-product problems (2005.09893v4)

Abstract: We show two asymmetric estimates, one on the number of collinear triples and the other on that of solutions to $(a_1+a_2)(a_1^{\prime\prime\prime}+a_2^{\prime\prime\prime})=(a_1^\prime+a_2^\prime)(a_1^{\prime\prime}+a_2^{\prime\prime})$. As applications, we improve results on difference-product/division estimates and on Balog-Wooley decomposition: For any finite subset $A$ of $\mathbb{R}$, [ \max{|A-A|,|AA|} \gtrsim |A|^{1+105/347},\quad \max{|A-A|,|A/A|} \gtrsim |A|^{1+15/49}. ] Moreover, there are sets $B,C$ with $A=B\sqcup C$ such that [ \max{E^+(B),\, E^\times (C)} \lesssim |A|^{3-3/11}. ]