* 1849 – Felix Klein, German mathematician ( d. 1925 )

See also the letter from Robert Gauss to Felix Klein on 3 September 1912.

In 1895, as a result of intervention on his behalf by Felix Klein, he obtained the position of Chairman of Mathematics at the University of Göttingen, at that time the best research-center for mathematics in the world.

Also in the last part of that century, Felix Klein and Henri Poincaré introduced a category of fractal that has come to be called " self-inverse " fractals.

Historically, the concept of fundamental group first emerged in the theory of Riemann surfaces, in the work of Bernhard Riemann, Henri Poincaré and Felix Klein, where it describes the monodromy properties of complex functions, as well as providing a complete topological classification of closed surfaces.

The Klein bottle was first described in 1882 by the German mathematician Felix Klein.

* Klein Bottle animation from 2010 including a car ride through the bottle and the original description by Felix Klein: produced at the Free University Berlin.

Felix Klein argued in his Erlangen program that one can consider various " geometries " by specifying an appropriate transformation group that leaves certain geometric properties invariant.

Some of Lie's early ideas were developed in close collaboration with Felix Klein.

Mathematician Felix Klein wrote about Abel:

* June 22 – Felix Klein, German mathematician ( b. 1849 )

an: Felix Klein

ca: Felix Klein

cs: Felix Christian Klein

da: Felix Klein

de: Felix Klein

et: Felix Klein

es: Felix Klein

fr: Felix Klein

fy: Felix Klein

it: Felix Klein

ht: Felix Klein

la: Felix Klein

* 1939 – Felix Pappalardi, American musician and recording producer ( Mountain ) ( d. 1983 )

However, further studies by Felix Bloch with Arnold Nordsieck, and Victor Weisskopf, in 1937 and 1939, revealed that such computations were reliable only at a first order of perturbation theory, a problem already pointed out by Robert Oppenheimer.

In order that the Yusupov name might not die out, the prince's father, Count Felix Felixovich Sumarokov-Elston ( October 5, 1856, Saint Petersburg – June 10, 1928, Rome, Italy ), General Governor of Moscow ( 1914 – 1915 ) ( son of Count Felix Nikolaievich Sumarokov-Elston ), took the surname of his wife, Princess Zenaida Nikolaievna Yusupova ( September 2, 1861, Saint Petersburg – November 24, 1939, Paris ) upon their marriage, on April 4, 1882 in Saint Petersburg, Russia.

January 16, 1939 cover featuring Felix Frankfurter

* Frankfurter, Felix, Mr. Justice Cardozo and Public Law, Columbia Law Review 39 ( 1939 ): 88 – 118, Harvard Law Review 52 ( 1939 ): 440 – 470, Yale Law Journal 48 ( 1939 ): 458 – 488.

* Henry L. Roberts " The Diplomacy of Colonel Beck " pages 579 – 614 from The Diplomats 1919 – 1939 edited by Gordon A. Craig & Felix Gilbert, Princeton University Press: Princeton, New Jersey, USA, 1953.

* Paul E. Zinner " Czechoslovakia: The Diplomacy of Eduard Benes " pages 100 – 122 from The Diplomats 1919 – 1939 edited by Gordon A. Craig & Felix Gilbert, Princeton University Press: Princeton, New Jersey, USA, 1953.

Allegheny Airlines began as All American Aviation Company, a business founded by du Pont family brothers Richard C. du Pont and Alexis Felix du Pont, Jr. in 1939.

He studied constitutional law at Harvard University in Cambridge, Massachusetts, under Felix Frankfurter, who was subsequently nominated and confirmed ( 1939 ) as an Associate Justice of the United States Supreme Court.

307 ( 1939 ) in the opinion by Justice Felix Frankfurter

In 1939 – 1940 he was law clerk to United States Supreme Court Justice Stanley F. Reed, and the following year he was clerk to Justice Felix Frankfurter, who had been one of his professors at Harvard.

Some American Jews, including Louis Brandeis and Felix Frankfurter, did try their hands at quiet diplomacy with some success, such that the quotas were being filled by 1939.

* Felix, ( a 2nd lieutenant in the reserves, imprisoned after 1939 in Starobielsk and probably murdered in the Katyn massacre );

Paul Herman Felix Kuypers ( 4 June 1939, Elst ( Overbetuwe ), Gelderland-d. near Ierapetra, Crete, Greece, 9 September 1971 ) was a Dutch agriculture expert, widely known in Ierapetra as the " Dutchman ".

* Felix Frankfurter was an Associate Justice of the Supreme Court of the United States ( 1939 – 62 ).

Princess Zinaida Nikolaievna Yusupova ( September 2, 1861, Saint Petersburg, Russia-November 24, 1939, Paris, France ) married Count Felix Felixovich Sumarokov-Elston ( October 5, 1856, Saint Petersburg, Russia-June 10, 1928, Rome, Italy ), General Governor of Moscow ( 1914 – 1915 ), son of Count Felix Nikolaievich Sumarokov-Elston.

* Felix A. Williams Elementary

* San Felix Elementary School