Thread: Convergent sequence

Let


Prove that

Originally Posted by zeh

Let


Prove that

Suppose q = p. Then every subsequence of q and p converge to q = min{q, p}, hence the minimum of q_n and p_n converges to q. On the other hand, suppose without loss of generality that q < p. Let r = (p + q)/2. Then there exists an N such that for all n >= N, |q - q_n| < r - q. Also, there exists an M such that for all m >= M, |p - p_n| < p - r. Let K = max{M, N}. Then q_k < (p + q)/2 < p_k for all k >= K, hence min{p_k, q_k} = q_k for all k >= K. Therefore the sequence converges to q.