Multiple choice

Let r(R) and s(S) be relations and let $S \le R$, the division operation R/S can be expressed as

  1. $\pi_{R-S}(R)$
  2. $\pi_{R-S}(R)-\pi_{R-S}((\pi_{R-S}(r)\times S) - \pi_{R-S}S(r))$
  3. $\pi_{R-S}(R)((\pi_{R-S}(r)\times S) - \pi_{R-S}S(r))$
  4. $\pi_{R-S}(r)\times S:$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

By definition of division operator

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