“…In Figure 5 we have depicted U ⋆ and η (both obtained via simulations) along the isotherm T ⋆ = 0.10 over a relatively large pressure interval, namely P ⋆ ∈ [2,10]. Values for the two quantities are depicted for structures labeled "b", "d", "e", "f", "g", and "h" over the respective ranges of stability; we note that mechanical stability (i.e., a positive compressibility) is guaranteed as long as η increases monotonically with increasing pressure.…”