2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/15609We propose a general scheme to create time sequences that fulfill given constraints but are random otherwise. Significance levels for nonlinearity tests are as usually obtained by Monte Carlo resampling. In a new scheme, constraints including multivariate, nonlinear, and nonstationary properties are implemented in the form of a cost function.4 pages, 3 figures, needs nolta.styChaotic Dynamicstext