Consider the following extended relational-algebra operators. Describe how toimplement each operation using sorting and using hashing. Semijoin (⋉θ): The multiset semijoin operator r⋉θs is defined as follows: if a tuple ri appears n times in r, it appears n times in the result of r⋉θ if there is at least one tuple sj such that ri and sj satisfy predicate θ; otherwise ri does not appear in the result.

Question 38 The correct statements are: If If Σ □ If If Ø, then Σ* has a subset that is not regular. Ø, then Σ* has a subset that is not context free. Ø, then Σ* has a subset that is not in D. Ø, then Σ* has a subset that is not in SD.

Define function p:cat represents set concatenation ◦, which concatenates every pair of strings from both sets using racket. We can specify set concatenation as p1 ◦ p2 = {u · v | u ∈ p1 ∧ v ∈ p2}. Alternatively, we give an inductive specification: ∅ ◦ p2 = ∅ p1 ◦ p2 = prefix(u, p2) ∪ (p'1◦ p2) if p1={u} ∪ p'1.

15. Code to Recurrence Relation What is the recurrence relation of the runtime of the following algorithm: T(n) represents the time it takes to complete func called with the parameter n value n. def func(n): if n == 0: return print(n) func(n//2) func(n//3) Pick ONE option T(n) = T(n-1) + T(n-2) + C; T(1) = C T(n) = T(n-2) + T(n-3) + C; T(1) = C T(n) = T(n/2) + T(n/3) + C; T(1) = C T(n) = T(n-5) + C; T(1) = C Clear Selection 81