On the pointwise convergence of the sequence of partial Fourier Sums along lacunary subsequences

Victor Lie

In his 2006 ICM invited address, Konyagin mentioned the following conjecture: if $S_{n}f$ stands for the $n$-th partial Fourier sum of $f$ and ${n_j}_j\subset \mathbb{N}$ is a lacunary sequ…