Figure 1
From: Further study on domains and quasihyperbolic distances
An essential tube \(T = T_{l,r,c}\) enclosing a portion \(\Omega _{T}\) of a domain Ω. The shaded region is the tth slice of \(\Omega _{T}\) and its (\(n-1\))-dimensional measure is at least c times the measure of the corresponding slice of T, which in turn is isometric to \(D^{n-1}_{r}\)