Turnaround mass versus the radius of the turnaround region in the HDCs of superclusters at different redshifts. For each HDC, the turnaround mass and radius are plotted at redshifts z = 0 (right point), z = 0.5 (middle point), and z = 1 (left point). Legend lists HDCs of superclusters plotted in the figure. Black lines show theoretical mass – radius relation for redshifts z = 0.0 (solid line), z = 0.5 (dashed line), and z = 1.0 (dot-dashed line) (Sect. 3.1).