How to denote domain and range Is there a common way to denote the domain or range of a function? I've seen things like
$ \cal{D}\left(f\right) $ and $ \cal{R}\left(f\right) $ for the domain and range, respectively, but I wasn't sure if there was a more explicit syntax for this (e.g., the way that cardinality has a specific syntax instead of just $\mathrm{card}\left(X\right)$, for instance).
I know that you alternatively mention the domain and range in the "mapping" notation of the function, e.g.:
$$
f: \cal{D} \to \cal{R}
$$
But I'm really just looking for a way to explicitly indicate the domain/range of a given function.

Unfortunately the term range means different things for different people.
In a function $f: \cal{D} \to \cal{R}$, we call $\cal{R}$ the codomain of $f$; it's the set where $f$ takes its values.
The image of $f$ is the set of values of $f$; it's a subset of the codomain, but usually smaller.
The term range means either codomain or image, and so is better avoided.
If you need notation, you may use $\text{dom}(f)$, $\text{codom}(f)$, $\text{im}(f)$.
