For a compact metrizable space
X, for a metric d on X, and for 𝜖 > 0, the number N(𝜖,X,d) is defined
as the minimum number of sets of d-diameter not exceeding 𝜖 required to
cover X. A classical theorem characterizes the topological dimension of X in
terms of the numbers N(𝜖,X,d). In this paper, two extensions of this result
are given: (i) a direct one, to separable metrizable spaces, involving totally
bounded metrics; (ii) a more complicated one, involving the set of continuous
totally bounded pseudometrics on the space as well as a special order on this
set.
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