2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/66706The paper is related to the following question of P.~L.~Ul'yanov: is it true that for any $2π$-periodic continuous function $f$ there is a uniformly convergent rearrangement of its trigonometric Fourier series? In particular, we give an affirmative answer if the absolute values of Fourier coefficients of $f$ decrease. Also, we study a problem how to choose $m$ terms of a trigonometric polynomial of degree $n$ to make the uniform norm of their sum as small as possible.Classical Analysis and ODEsCombinatorics42A20, 42A05, 42A61text