René Gâteaux, killed in 1914 -----------------------------
René Gâteaux was born in 1889 in Vitry-le-François (Marne). After completing his secondary education in Reims, he entered the École normale supérieure in 1907. A scholarship awarded in 1913 took him to Rome, where he attended lectures by Vito Volterra. This Francophile mathematician encouraged him to study functional analysis and differential calculus. Gâteaux sought to lay the foundations for a theory of integration in infinite dimensions. On returning in June 1914, he wrote a paper defining the differential of a function of several variables at a point in a way more general than the commonly accepted definition. Today, this is known as Gâteaux differentiability.
Although he had planned to return to Italy, he was mobilized in August. On 3 October, he was cut down by a burst of submachine-gun fire at Rouvroy, south of Lens (Pas-de-Calais), while his regiment was defending the area during the "Race to the Sea." Jacques Hadamard recognized the quality of his research as early as 1915 and arranged for him to receive the Francœur Prize the following year. Thanks to Paul Levy, his manuscripts were also published posthumously.
The Levi brothers: Eugenio -------------------------------