 Let ("X", "T") be a Hausdorff topological space and let Σ be a σ-algebra on "X" that contains the topology "T" (so that every open set is a measurable set, and Σ is at least as fine as the Borel σ-algebra on "X").Then a measure "μ" on ("X", Σ) is called strictly positive if every non-empty open subset of "X" has strictly positive measure.In more condensed notation, "μ" is strictly positive if and only if