## 4-44. Felix Klein

Felix Klein (1849–1925) and Henri Poincaré exchanged numerous
letters, mostly during the period from 12 June 1881 to 22 September
1882, which was one of intense mathematical activity for both men, in
the new field of automorphic functions, and on the uniformization
theorem. The letters from this period were edited in 1923 by N. E. Nörlund
(1923), and reedited by Pierre Dugac, with French
translations of Klein’s letters (Dugac, 1989).^{1}^{1}endnote:
^{1}
The
twenty-six letters of the early Poincaré-Klein exchange were
translated from French to English by Robert Burns; see Saint-Gervais (2016). An overview of this
celebrated exchange is provided in
Klein (1926, 374–381),
Fricke et al. (1923, 577–586),
Dieudonné (1982),
Gray and Walter (1997b),
Gray (2000),
Gray (2013, chap. 3),
and Rowe (2018, chap. 11). On
Klein’s life and work, see the detailed biography by Tobies (2019).

During the two decades following their early exchange, Klein and
Poincaré collaborated on an international project to index scientific
publications. They exchanged several letters on this topic, and both
participated in a meeting held in London in August, 1899
(Armstrong et al., 1899).
Another, even more ambitious project was launched by
Klein in the closing years of the nineteenth century: the
*Encyclopedia of Mathematical Sciences Including
Applications*. While the *Encyclopedia* took form in Germany,
and was organized in line with German academic standards, it was
considered by its organizers and collaborators to be an
*international* endeavor, reflecting the notion that mathematical results,
while obtained in various settings, are an international asset (Schappacher, 2022, 51).
A French-language version of the encyclopedia was planned, led by Jules
Molk, and several volumes were published.^{2}^{2}endnote:
^{2}
Molk’s death in
1914, and the subsequent outbreak of the First World War put a
strain on the collaborative project, and after 1916, the French
version of the encyclopedia was abandoned. For a comparison of the
two versions of the encyclopedia, see Gispert (2001). Molk
sollicited a contribution from Poincaré
(§ 4-59-1)
in 1901, but nothing came of it.

Time-stamp: " 1.08.2022 18:16"

### Notes

- 1 The twenty-six letters of the early Poincaré-Klein exchange were translated from French to English by Robert Burns; see Saint-Gervais (2016).
- 2 Molk’s death in 1914, and the subsequent outbreak of the First World War put a strain on the collaborative project, and after 1916, the French version of the encyclopedia was abandoned. For a comparison of the two versions of the encyclopedia, see Gispert (2001).

## References

- International catalogue of scientific literature: Report of the Provisional International Committee. Science 10 (249), pp. 482–487. link1 Cited by: 4-44. Felix Klein.
- Actes du VIe congrès du regroupement des mathématiciens d’expression latine, Luxembourg, 7–12 septembre 1981. Gauthier-Villars, Paris. Cited by: J. Dieudonné (1982).
- La découverte des fonctions fuchsiennes. See Actes du VIe congrès du regroupement des mathématiciens d’expression latine, Luxembourg, 7–12 septembre 1981, Congrès du Groupement des mathématiciens d’expression latine, pp. 3–23. Cited by: 4-44. Felix Klein.
- Henri Poincaré, la correspondance avec des mathématiciens (de J à Z). Cahiers du séminaire d’histoire des mathématiques 10, pp. 83–229. link1 Cited by: 4-44. Felix Klein.
- Felix Klein Gesammelte mathematische Abhandlungen, Volume 3. Springer, Berlin. link1 Cited by: 4-44. Felix Klein.
- The German and French editions of the Klein-Molk Encyclopedia: contrasted images. In Changing Images in Mathematics: From the French Revolution to the New Millennium, U. Bottazzini and A. Dahan Dalmedico (Eds.), Studies in the History of Science, Technology and Medicine, Vol. 13, pp. 93–112. Cited by: endnote 2.
- Henri Poincaré: Trois suppléments sur la découverte des fonctions fuchsiennes. Akademie-Verlag, Berlin. link1 Cited by: J. Gray and S. A. Walter (1997b).
- Introduction. See Henri Poincaré: Trois suppléments sur la découverte des fonctions fuchsiennes, Gray and Walter, pp. 1–25. link1 Cited by: 4-44. Felix Klein.
- Linear Differential Equations and Group Theory from Riemann to Poincaré. Birkhäuser, Boston. Cited by: 4-44. Felix Klein.
- Henri Poincaré: A Scientific Biography. Princeton University Press, Princeton. link1 Cited by: 4-44. Felix Klein.
- Vorlesungen über die Entwicklung der Mathematik im 19. Jahrhundert, Volume 1. Julius Springer, Berlin. link1 Cited by: 4-44. Felix Klein.
- Correspondance d’Henri Poincaré et de Felix Klein. Acta mathematica 39, pp. 94–132. link1 Cited by: 4-44. Felix Klein.
- A Richer Picture of Mathematics: the Göttingen Tradition and Beyond. Springer, Cham. Cited by: 4-44. Felix Klein.
- Uniformization of Riemann Surfaces: Revisiting a Hundred-Year-Old Theorem. European Mathematical Society, Zurich. link1, link2 Cited by: endnote 1.
- Framing Global Mathematics: The International Mathematical Union between Theorems and Politics. Springer Nature, Cham. link1, link2 Cited by: 4-44. Felix Klein.
- Felix Klein: Visionen für Mathematik, Anwendungen und Unterricht. Springer, Berlin. link2 Cited by: 4-44. Felix Klein.