# What does $\mathbf{Q}^+$ mean in approximation texts?

Often, in a lot of texts concerning approximation algorithms I see the following notation (for example, here in page 19 of the PDF or the first page of the introduction):

... and a cost function on vertices $c:V\to \mathbf{Q}^+$ ...

Is this just the positive rationals? Or is this something else?

• I agree but what does "positive" mean? Half the world says "positive" for $x\geq 0$ and "strictly positive" for $x>0$; the other half says "nonnegative" for $x\geq 0$ and "positive" for $x>0$. (Which is why I prefer to write $\mathbb{Q}_{\geq 0}$ or $\mathbb{Q}_{> 0}$; or superscripts, if you prefer.) – David Richerby Sep 29 '16 at 9:17