2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/68285We consider the question whether the trigonometric system can be equivalent to some rearrangement of the Walsh system in L_p for some p<>2. We show that this question is closely related to a combinatorial problem. This enables us to prove non-equivalence for a number of rearrangements. Previously this was known for the Walsh-Paley order only.18 pages, to be published in Stud. MathFunctional Analysis42C20 (primary) 42C10, 46B15 (secondary)text