Let f : X → Y be quasi-open. We show that: (1) If A ⊂ X is open, f｜A is quasi-open, (2) f : X → f (X) is quasi-open. (3) And let f_α : X_α → Y_α be quasi-open. Then IIf_α : IIX_α → IIY_α, defined by {χ_α} → {f_α(χ_α)}, is quasi-open. (4) Lastly, if f_i : X_i → Y are quasi-open, i = 1, 2, then F : X₁◎ X₂ → Y, defined by F(χ) = f_i(χ), χ ∈ X_i, is also quasi-open.