4-49. 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 Nörlund (1923), and reedited by Dugac, with French translations of Klein’s letters (Dugac, 1989). An overview of this celebrated exchange is provided in Klein (1926, 374–381), Klein (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).