[EN] Given A ⊆ R, the Hattori space H(A) is the topological space (R, τA) where each a ∈ A has a τA-neighborhood base {(a−ε, a+ε) : ε > 0} and each b ∈ R − A has a τA-neighborhood base {[b, b + ε) : ε > 0}. Thus, τA may ...