Hausdorff’s forgotten proof that almost all numbers are normal

Mathematische Semesterberichte - Tập 68 - Trang 273-282 - 2021
Edmund Weitz1
1Hamburg University of Applied Sciences, Hamburg, Germany

Tóm tắt

In 1914, Felix Hausdorff published an elegant proof that almost all numbers are simply normal in base 2. We generalize this proof to show that almost all numbers are normal. The result is arguably the most elementary proof for this theorem so far and should be accessible to undergraduates in their first year.

Tài liệu tham khảo

Borel, É.: Les probabilités dénombrables et leurs applications arithmétiques. Suppl. Rend. Circ. Mat. Palermo 27, 247–271 (1909) Doob, J.L.: The development of rigor in mathematical probability. Am. Math. Mon. 103(4), 586–595 (1996) Filip, F., Šustek, J.: An elementary proof that almost all real numbers are normal. Acta Univ. Sapientiae Math. 2(1), 99–110 (2010) Hardy, G.H., Wright, E.M.: An Introduction to the Theory of Numbers. Clarendon Press, Oxford (1938) Hausdorff, F.: Grundzüge der Mengenlehre. Veit & Comp., Leipzig (1914) Kac, M.: Statistical Independence in Probability, Analysis and Number Theory. Carus Math. Monogr., vol. 12. Wiley, New York (1959) Nillsen, R.: Normal numbers without measure theory. Am. Math. Mon. 107(7), 639–644 (2000) Niven, I.: Irrational Numbers. Carus Math. Monogr., vol. 11. Wiley, New York (1956)