A topological space X = (X, τ) that contains a countable subset which is τ-dense.

A^1(D, dλ^2) | A^2(D, dλ^2) | A^ formal p (D, dλ^2) | H_2^ formal s (R^n, dx^n) | H_ formal p ^ formal s (R^n, dx^n) | ℬ(D, dλ^2) | C^0([a, b]) | C^∞([a, b]) | C^ formal k ([a, b]) | C^ω([a, b]) | C^0(R^n) | C^∞(R^n) | C^ formal k (R^n) | C^ω(R^n) | CMO(R^n, dx^n) | a^1(D, dλ^2) | a^2(D, dλ^2) | a^ formal p (D, dλ^2) | ℬ^h(D, dλ^2) | h^2 | ...

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