Are there any customary notation for: $(X\times Y) \cap f \ne \emptyset$ ($f$ is a binary relation, $X$ and $Y$ are sets)?
For example $\{ f(x) | x\in X \}$ is commonly denoted as $f[X]$. But are there any common notation for the above formula?
Are there any customary notation for: $(X\times Y) \cap f \ne \emptyset$ ($f$ is a binary relation, $X$ and $Y$ are sets)?
For example $\{ f(x) | x\in X \}$ is commonly denoted as $f[X]$. But are there any common notation for the above formula?