Possible Duplicate:
Question about set notation
Suppose we have that $\ f:]a,b[\rightarrow\mathbb{R}$.
What is $]a,b[$?
I know what $[a,b]$, $(a,b)$, $[a,b)$ are.
I would usually google but I don't know what keyword to use. Let me know if this is too simple/inappropriate for Math.SE and I'll delete.