1
$\begingroup$

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?

  • 0
    From context, $X$ and $Y$ are sets. But what is $f$?2011-07-15
  • 0
    The notation $X \times Y \cap f$ is ambiguous. Do you mean $(X \times Y) \cap f$ or $X \times ( Y \cap f)$? A binary relation is a set of ordered pairs. The two formulas give different results. When you write formulas with different binary relations it is helpful to use parentheses to clarify the formula.2011-07-15
  • 0
    The clearest notation, in my opinion, would just be to write $\{(x,y) \in X \times Y : f(x,y)\}$.2011-07-15

1 Answers 1