**André Bloch** was a French mathematician who worked in complex analysis. He spent most of his life in a psychiatric hospital.

- André and Georges were less than a year apart in age and ended up in the same class at the lycée in Besançon.
- André had already displayed his interest in the abstract properties to which he would later make such significant contributions.
- André was last in my class of eleven students.
- Both André and Georges were injured while serving.
- André served as second-lieutenant in the artillery and was attached to the headquarters of General Noël Édouard, Vicomte de Curières de Castelnau, who commanded the Second French Army at the heights of Grand Couronné near Nancy.
- André Bloch was part of the French forces here for several months before, during a heavy German bombardment, he fell from the top of an observation post.
- Like André, he was unfit to return to the fighting and, in October 1917, he returned to his academic studies at the École Polytechnique.
- Pólya, like Hadamard, communicated with Bloch by correspondence.
- Szolem Mandelbrojt also seems to have befriended Bloch and visited him in the asylum.
- He is thought to have been Bloch's last visitor before he died.
- Since Bloch was Jewish, he realised that he was in danger when France was occupied by Germany during World War II.
- For example his paper Sur une généralisation du théorème du Guldin Ⓣ(On a generalization of the theorem of Guldin) (1941) appeared under the pseudonym René Binaud while three other of Bloch's articles in 1941 and 1942 appeared under the pseudonym Marcel Segond.
- Bloch was a model patient who refused to go out saying "Mathematics is enough for me".
- It is likely that Bloch's wartime injury had damaged his prefrontal cortex and caused his condition.
- Of his mathematical results, Bloch is best known for "Bloch's theorem".
- Bloch's theorem provides a touch of beauty, a surprising quantitative invariance to the class of normalized hyperbolic Riemann surfaces.
- Bloch's theorem, which appears in his 1925 paper, Les théorèmes de M Valiron sur les fonctions entières et la théorie de l'uniformisation Ⓣ(Valiron's theorems on entire functions and the theory of standardization), was (as the title of the paper suggests) inspired by a result by Georges Valiron.
- The name of André Bloch is attached to magnificent works on the theory of analytic functions of a complex variable and on many different areas of geometry, in particular geometrical inversion and non-Euclidean geometry for which he had a particular fondness.

Born 20 November 1893, Besançon, France. Died 11 October 1948, Paris, France.

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**O’Connor, John J; Robertson, Edmund F**: MacTutor History of Mathematics Archive