What does $0\le x,y\le1$ mean? See the red circled part in the image below for an example.
I first thought it meant: $x\ge0$ and $y\le1$
Then I thought it meant: $0\le x\le y \le 1 $
But, based on the green part, I believe it means: $x$ and $y$ are in $[0,1]$
Is this notation unambiguous? In probability, the comma means $\bigcap$, so, to me, these are "separate" statements, as in (1) and not (3).