The set of values for which a function is defined.
Example
The domain of the function \(f : \mathbb{N} → \mathbb{Q}\space | \space f(x) = \dfrac{1}{x}\) is \(\mathbb{N} \setminus 0\).
Therefore: dom(f) = \(\mathbb{N}^{*}\).
The domain of the function \(f : \mathbb{N} → \mathbb{Q}\space | \space f(x) = \dfrac{1}{x}\) is \(\mathbb{N} \setminus 0\).
Therefore: dom(f) = \(\mathbb{N}^{*}\).