Let A be a set of integers which is dense in a finite interval. We establish upper and lower bounds for the longest regularly-spaced and convex sequences in A and in $A-A$.

中文翻译：

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密集的整数集中的长规则间隔和凸序列

设A为一组在有限间隔内密集的整数。我们为A和A中最长的规则间隔和凸序列确定上限和下限$\mathrm{一种}-\mathrm{一种}$。