I don't know what it is even called so I cannot really type it out properly, sorry.
I've seen things like $X$|_|$[0,1)$. The symbol in question looks like $\cup$ but without curvy, round bits, its like the bottom half of a square.
I don't know how else to describe it and it look bizarre.
Can anyone tell me? Thank you
Best Answer
$A\sqcup B$ is just $A\cup B$, but it gives the information that $A$ and $B$ are disjoint, i.e. $A\cap B=\emptyset$.
In probability theory, this notation can also be used for independence. For example, $X\sqcup Y$ means that the random variables $X$ and $Y$ are independent.