How does one denote the set of all positive real numbers? What is the "standard" way to denote all positive (or non-negative) real numbers? I'd think $$ \mathbb R^+ $$ but I believe that that is usually used to denote "all real numbers including infinity". So is there a standard way to denote the set $$ \\{x \in \mathbb R : x \geq 0\\} \; ?$$

Not that I knew of. There are many, e.g.

* $\mathbb{R^+_0}$,
* $\mathbb{R^+}$ and
* $[0, \infty)$.