What are the GLB and LUB of the sets A = {3, 9, 12} and B = {1, 2, 4, 5, 10}, if they exist, in the poset (Z⁺, /)?
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Correct answer: A. A (GLB 3, LUB 36); B (GLB 1, LUB 20)
Explanation
Under divisibility, GLB = gcd and LUB = lcm. gcd(3, 9, 12) = 3, lcm = 36; gcd(1, 2, 4, 5, 10) = 1, lcm = 20.
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