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**scorpion007** What is the composition of the relation | (divides) and $\displaystyle \le$?My general interpretation:

Let $\displaystyle R_1$ be the | relation, and $\displaystyle R_2$ be $\displaystyle \le$. $\displaystyle R_1 \circ R_2$ should be the set of all points $\displaystyle (s, u)$ where $\displaystyle s$ divides some $\displaystyle t \le u$.

If this is correct, (I'm not sure) how would I express this as set-builder notation?

$\displaystyle R_1 \circ R_2 = \lbrace (s, u)\; |\; s | t,\; t \le u \rbrace$ ?