Evolution of the maximum line-mass in the simulation of a filament of f_cyl = 0.9 for a perturbation wavelength of three times shorter, shown in light blue, and 2.22 times shorter, shown in dark blue, than the dominant wavelength. In the former case the core does not collapse directly but the line-mass oscillates with values above the critical line-mass until eventually a single collapsing core forms on the dominant wavelength.