Let An=(1n,n+1n]A_n = \left( \frac{1}{n}, \frac{n+1}{n} \right]An=(n1,nn+1] for n∈Nn \in \mathbb{N}n∈N (natural numbers, starting from 1). Determine the set S=⋃n=1∞(⋂k=n∞Ak)S = \bigcup_{n=1}^{\infty} \left( \bigcap_{k=n}^{\infty} A_k \right)S=⋃n=1∞(⋂k=n∞Ak).
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∅\emptyset∅
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