“…) is lower semicontinuous on X (see [7], [8]) and continuous on any finite-dimensional subspace. Given any ε > 0, for each point x of the compact set K, consider a δ x -neighbourhood O δx (x), where δ x ∈ (0, ε/4), of this point such that ϱ(y, M ) < ϱ(x, M ) + ε/4 for all y ∈ O δx (x) (this is possible since the metric function is continuous).…”