Léopold Leau (1868-1943) was a French mathematician,. primarily known for his ties to international auxiliary languages.
The Delegation for the Adoption of an International Auxiliary Language was founded on 7 January 1901 on Leau's initiative.. He co-wrote with Prof. Louis Couturat the monumental Histoire de la Langue Universelle (1903) and its supplement Les Nouvelles Langues Internationales (1907)..
Leau studied at the École normal supérieure in Paris and received his doctorate there in April 1897.Die Dissertation Étude sur les équations fonctionnelles à une ou à plusieurs variables erschien in: Annales de la Faculté des Sciences de Toulouse: Mathématiques, Série 1, Band 11 (1897), Heft 2, Seiten E.1-E.110. Digitalisat bei Numdam: Teil 1, Teil 2 Later he was a professor at the University of Nancy . There he was Dean of the Faculté des Sciences from 1931–34. In his dissertation, Leau examined, among other things, the iteration behavior of holomorphic functions in the environment of a rationally indifferent fixed point. His results are known today under the name (Leau-Fatou) Flower Theorem . They play an important role in the complex dynamics.
References
Daniel S. Alexander: A history of complex dynamics: from Schröder to Fatou and Julia. (Aspects of Mathematics), Vieweg, Braunschweig 1994, . Chapter 5 describes Leau's contributions.