The discussion focuses on proving the inequality $18 < \sum_{i=2}^{99} \frac{1}{\sqrt{i}} < 19$. Participants explore the implications of the inequality, particularly how it relates to the expressions $\sqrt{n+1} + \sqrt{n} > 2\sqrt{n}$ and $\sqrt{n-1} + \sqrt{n} < 2\sqrt{n}$. The reciprocal forms of these inequalities are also examined, leading to the conclusion that $\frac{1}{\sqrt{n+1} + \sqrt{n}} < \frac{1}{2\sqrt{n}} < \frac{1}{\sqrt{n-1} + \sqrt{n}}$. The thread emphasizes the validity and effectiveness of the proposed solutions. Overall, the discussion provides a thorough mathematical exploration of the inequality.