β₀ persistence diagrams in a temporal sequence of magnetograms of active region #12673, constructed from the set of points (pixels) with positive magnetic field intensities greater than 200 Gauss. The co-ordinates of each point (x, y) on a persistence diagram represent the birth and death times of a β₀ feature. Note that all the features lie above the x = y line in the diagrams since a feature cannot die before it is born. In terms of number of connected components at various scales, these diagrams reveal a clear change in the topology of the field structure around the X2.2-class flare that took place at 0910 UT on 6 September 2017.