“…Informally, for every pair of different balls, B Rn (X n ) and B Rm (X m ) with a non-empty intersection, the ball B Rn (X n ) gets deleted if W n ≤ W m ; this procedure deletes both balls if W n = W m . To be a bit more formal, we use the notation borrowed from Kuronen and Leskelä (2013): let (1.4) N x,r,w = (x , r , w ) ∈ R d × R + × R + \{x, r, w} : B r (x ) ∩ B r (x) = ∅ ;…”