Any sequence of (r−1)(s−1) + 1 distinct reals contains a monotone subsequence: either increasing of length r or decreasing of length s. Classical pigeonhole argument on labels (incr_len, decr_len). 1935 paper also contains the…
Any sequence of (r−1)(s−1) + 1 distinct reals contains a monotone subsequence: either increasing of length r or decreasing of length s. Classical pigeonhole argument on labels (incr_len, decr_len). 1935 paper also contains the…