Richard Courant
Richard Courant (born January 8, 1888 in Lublinitz , Upper Silesia , † January 27, 1972 in New York ) was a GermanAmerican mathematician .
Life
Richard Courant was born in Lublinitz , Silesia , in 1888 . His father Siegmund Courant was a small businessman who came from a large Jewish family. His mother Martha Courant, née Freund, was the daughter of a businessman from neighboring Oels . Edith Stein was a paternal cousin of Richard Courant.
His parents often moved in his youth: to Glatz , Breslau and finally to Berlin in 1905. Richard first attended high school in Glatz and later the humanistic KönigWilhelmGymnasium in Breslau. After initial teething problems, he was considered a very good student there. The father's business was not doing very well and he was declared bankrupt in 1901. Finally, the father decided to move his business activities to Berlin. Richard Courant, however, who had started early to earn money as a private tutor alongside school, stayed behind in Wroclaw. In the winter semester of 1906/07 he began studying at the University of Breslau , initially in physics and later in mathematics. He found the lectures rather unsatisfactory and went to Zurich and then to Göttingen , where he became David Hilbert's assistant . In 1910 Courant received his doctorate there on the subject of the application of Dirichlet's principle to the problems of conformal mapping and completed his habilitation in 1912.
He was drafted into the First World War on August 8, 1914 , and five days later took part in the lossmaking advance through Belgium to France. There he experienced a "disastrous communication chaos ", whereupon he campaigned for the development of a new type of terrestrial telegraph . He got Carl Runge , Peter Debye and Paul Scherrer to collaborate . He was soon wounded and discharged from the military. He then returned to Göttingen, where, after two years in Münster, he was appointed professor in 1922 and later head of the mathematical institute. From 1925 he was a member of the Göttingen Academy of Sciences .
After the seizure of power , Courant left Germany in the summer of 1933. He spent a year in Cambridge and then went to New York , where he became a professor in 1936. There he built a mathematical research center with Kurt Friedrichs , whom he brought from Göttingen, and the young Peter Lax . The Courant Institute for Mathematical Sciences (as it has been called since 1964) at New York University is one of the world's most respected institutes for applied mathematics . In 1953 Courant was elected to the American Philosophical Society and in 1955 to the National Academy of Sciences .
After a short marriage to Nelly Neumann, Courant was married to Nerina ( Nina ) Runge, a daughter of Carl Runge, for the second time since 1919 . His son Ernest Courant was a wellknown physicist, and his daughter Gertrude Moser is a biologist and wife of the mathematician Jürgen Moser .
plant
Richard Courant founded and successfully led a mathematical institute. He was also an outstanding mathematician. He developed the finite element method by Walter Ritz ( method by Ritz ), which was later widely used by engineers and natural scientists (but did not attract any attention from engineers when Courant was published in 1943), and clarified its mathematical principles. The method today is u. a. a standard procedure for the numerical solution of partial differential equations , because concrete error estimates are often possible. It is used as standard in quantum mechanics in particular .
His textbook Methods of Mathematical Physics with David Hilbert is a standard work even more than 80 years after its publication. It is based on lectures by Hilbert, but is almost entirely written by Richard Courant.
There is also a twovolume textbook from the 1920s ( lectures on differential and integral calculus ) for students in the first two semesters. These two volumes are also timeless and are therefore still on sale (as a “contrast”, so to speak) because, in contrast to the more abstract modern illustrations, they are very clear and understandable.
In the field of numerical flow simulation , Richard Courant is best known for the CourantFriedrichsLewy number , which is important for the calculation of hyperbolic partial differential equations. Furthermore, the CourantFischer theorem is named after him, which gives a representation of the eigenvalues of a symmetrical or Hermitian matrix as a minimum or maximum Rayleigh quotient (minimummaximum principle).
In his dissertation Richard Courant dealt with the Dirichlet principle and its application in the theory of uniformity. He returned to this in later works on minimal surfaces and conformal mapping.
His book with Herbert Robbins “Was ist Mathematik?” (First published in 1941) is considered a firstclass introduction.
Honors
 1955: Honorary doctorate from the TH Darmstadt .
 1959: Large Cross of Merit with Star of the Federal Republic of Germany
Fonts
 with Herbert Robbins : What is mathematics? 5th edition. Springer Verlag, 2000, ISBN 354063777X
 with Adolf Hurwitz : Function theory. 4th edition (with Helmut Röhrl ) Springer Verlag, 1922/1964 ( lectures on elliptical functions and general function theory by Adolf Hurwitz, edited and supplemented by a section on geometric function theory by Courant )
 Methods of mathematical physics. 2 vols. Springer Verlag, 1968 (first 1924, 1930), completely revised in the English edition, Interscience, 1953, 1961, online: Methods of mathematical physics 1924

Lectures on differential and integral calculus. 2 vols. Springer Verlag, 1970 (first 1924)
 English edition with Fritz John : Introduction to calculus and analysis , 2 volumes, Springer Verlag 1989
 Dirichlets principle, conformal mappings and minimal surfaces. Interscience, 1950
 with Kurt Friedrichs : Supersonic Flow and Shock Waves. Interscience, 1961 (first published in 1948)
 Via conformal mapping of areas, which are not broken up by all return cuts, onto plain normal areas. Mathem. Magazine Vol. 3, Issue 1/2, p. 9, Springer, Berlin (1919).
 About the theory of linear partial difference equations . Message d. Society d. Science to Göttingen. Mathem. Phys. Class, Volume 23, 1925
 Remarks on the question of the numerical resolution of boundary value problems that arise from the calculus of variations. Message d. Society d. Science to Göttingen. Mathem. Phys. Class, volume 1925
 Via a class of covariant functional expressions that arise from variation problems . Message d. Society d. Science to Göttingen. Mathem. Phys. Class, Volume 18, 1925
 About direct methods for variation and boundary value problems , annual report of the German Mathematicians Association 1926.
 with Kurt Friedrichs, Hans Lewy: About the partial difference equations of mathematical physics. Mathematische Annalen, Volume 100, 1928, pp. 3274
literature
 Constance Reid: Richard Courant. 1888–1972  the mathematician as a contemporary , Springer Verlag 1979, ISBN 0387091777 .
Web links
 Literature by and about Richard Courant in the catalog of the German National Library
 John J. O'Connor, Edmund F. Robertson : Richard Courant. In: MacTutor History of Mathematics archive .
 Short biography at the University of Göttingen
 History of Mathematics at the University of Münster, a. a. Courant biography, pdf
 Richard Courant in the Mathematics Genealogy Project (English)
 Member Directory: Richard Courant. National Academy of Sciences, accessed December 15, 2015 (Biographical Memoir by Peter D. Lax ).
Individual evidence
 ↑ Arne Schirrmacher: Physics in the Great War , Physics Journal 13 (2014), No. 7, pp. 43–48.
 ↑ Hans Schäfer: The eavesdropping of longdistance calls and the earth telegraphy in the field. In: Polytechnisches Journal . 334, 1919, pp. 9397.
 ↑ Holger Krahnke: The members of the Academy of Sciences in Göttingen 17512001 (= Treatises of the Academy of Sciences in Göttingen, PhilologicalHistorical Class. Volume 3, Vol. 246 = Treatises of the Academy of Sciences in Göttingen, MathematicalPhysical Class. Episode 3, vol. 50). Vandenhoeck & Ruprecht, Göttingen 2001, ISBN 3525825161 , p. 62.
 ↑ Courant Variational methods for the solution of problems of equilibrium and vibrations , Bulletin AMS, Volume 49, 1943, pp. 1–23, (Online)
personal data  

SURNAME  Courant, Richard 
BRIEF DESCRIPTION  GermanAmerican mathematician 
DATE OF BIRTH  January 8, 1888 
PLACE OF BIRTH  Lublinitz , Upper Silesia 
DATE OF DEATH  January 27, 1972 
Place of death  new York 