Proof

(related to Lemma: Decreasing Sequence of Suprema of Extended Real Numbers)


Thank you to the contributors under CC BY-SA 4.0!

Github:
bookofproofs


References

Bibliography

  1. Forster Otto: "Analysis 1, Differential- und Integralrechnung einer Veränderlichen", Vieweg Studium, 1983

Footnotes


  1. Note: $D_n$ can be visualized as $$\begin{array}{c|ccccc} n&D_n&&&&\\ \hline 1&a_1&a_2&a_3&a_4&\ldots\\ 2&&a_2&a_3&a_4&\ldots\\ 3&&&a_3&a_4&\ldots\\ 4&&&&a_4&\ldots\\ \vdots&&&&&\ddots\\ \end{array}$$