Talk:Vector fields on spheres
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Definition of the Radon-Hurwitz numbers?
[edit]- The numbers ρ(n) are the Radon-Hurwitz numbers, so-called from the earlier work of Johann Radon (1922) and Adolf Hurwitz (1923) in this area. A recurrence relation is easy to give.
...and? Michael Hardy 00:13, 10 November 2006 (UTC)
The definition given here is one off from the definitions of the following sources. Rajwade, A. R. (1993). Squares. London Mathematical Society Lecture Note Series. Vol. 171. Cambridge University Press. p. 127. ISBN 0-521-42668-5. Zbl 0785.11022. Lam, Tsit-Yuen (2005). Introduction to Quadratic Forms over Fields. Graduate Studies in Mathematics. Vol. 67. American Mathematical Society. p. 126. ISBN 0-8218-1095-2. Zbl 1068.11023. These are in the context of finding formulae that express the product of a sum r squares and a sum of s squares as a sum of n squares. When s=n, the Radon–Hurwitz numbers gives a possible value for r. What is the resolution here? Additional: the definition in Porteous seems different again. Deltahedron (talk) 18:04, 26 August 2012 (UTC)
- Adams (1962) defines ρ in accordance with the two references I cite above (referring back to Radon/Hurwitz) and his theorem is that there are ρ-1 but not ρ independent vector fields on a sphere. I am rewording accordingly. Deltahedron (talk) 18:12, 26 August 2012 (UTC)
Years of life and results
[edit]The article states, that so-called from the earlier work of Johann Radon (1922) and Adolf Hurwitz (1923) in this area.
The article for the Adolf Hurwitz says that he died in 1919.
What the date 1923 after Hurwitz name stays for? Is it post mortem publication or english translation of the earlier work?
Or may be an error?
--Inkittenus (talk) 17:47, 25 April 2010 (UTC)
- According to Rajwade, it was published posthumously. Deltahedron (talk) 11:14, 26 August 2012 (UTC)
needs additional citation flag
[edit]The occurence of the needs additional citation flag for the article in its current form seems not justified to me - references 1-3 seem to contain everything discussed in the article. If there are doubts about the dates of the work of Radon and Hurwitz these dates could just be removed; are they relevant for an encycopledic article? — Preceding unsigned comment added by Thomas.schick (talk • contribs) 18:31, 10 November 2018 (UTC)