论文标题
多个相关序列不可与nil序列近似
Multiple correlation sequences not approximable by nilsequences
论文作者
论文摘要
我们表明，有一个措施推广系统$（x，\ m马斯克{b}，μ，t）$以及函数$ f_0，f_1，f_1，f_2 \ in l^{\ infty}（μ）$ \ cdot t^{2n} f_2dμ$不是$ 2 $ -Step nilSequences的大致组合组合。
We show that there is a measure-preserving system $(X,\mathscr{B}, μ, T)$ together with functions $F_0, F_1, F_2 \in L^{\infty}(μ)$ such that the correlation sequence $C_{F_0, F_1, F_2}(n) = \int_X F_0 \cdot T^n F_1 \cdot T^{2n} F_2 dμ$ is not an approximate integral combination of $2$-step nilsequences.
