- Hermann Weyl
Infobox Scientist

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name = Hermann Klaus Hugo Weyl

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caption = Hermann Weyl (left) andErnst Peschl (right)

birth_date = Birth date|1885|11|9|df=y

birth_place =Elmshorn ,Germany

death_date = Death date and age|1955|12|8|1885|11|9|df=y

death_place =Zurich ,Switzerland

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fields =Mathematical physics

workplaces =Institute for Advanced Study University of Göttingen ETH Zurich

alma_mater =University of Göttingen

doctoral_advisor =David Hilbert

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known_for = Seelist of topics named after Hermann Weyl

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footnotes =**Hermann Klaus Hugo Weyl**(9 November 1885 –8 December 1955 ) was a Germanmathematician . Although much of his working life was spent inZürich ,Switzerland and then Princeton, he is associated with theUniversity of Göttingen tradition of mathematics, represented byDavid Hilbert andHermann Minkowski . His research has had major significance fortheoretical physics as well as pure disciplines includingnumber theory . He was one of the most influential mathematicians of the twentieth century, and an important member of theInstitute for Advanced Study during its early years.Weyl published technical and some general works on

space ,time ,matter ,philosophy ,logic ,symmetry and thehistory of mathematics . He was one of the first to conceive of combininggeneral relativity with the laws ofelectromagnetism . While no mathematician of his generation aspired to the 'universalism' ofHenri Poincaré or Hilbert, Weyl came as close as anyone.Michael Atiyah , in particular, has commented that whenever he examined a mathematical topic, he found that Weyl had preceded him ("The Mathematical Intelligencer" (1984), vol.6 no.1).The similarity of the names sometimes led to his being confused with

André Weil . A joke for mathematicians was that, each being of great renown, this was a rare example where such mistakes would not cause offence for either party.**Biography**Weyl was born in

Elmshorn , a town nearHamburg , inGermany .From 1904 to 1908 he studied mathematics and physics in both

Göttingen andMunich . His doctorate was awarded at theUniversity of Göttingen under the supervision ofDavid Hilbert whom he greatly admired. After taking a teaching post for a few years, he left Göttingen for Zürich to take the chair of mathematics in theETH Zurich , where he was a colleague ofAlbert Einstein , who was working out the details of the theory of general relativity. Einstein had a lasting influence on Weyl who became fascinated by the mathematical physics. Weyl metErwin Schrödinger in 1921, who was appointed Professor at theUniversity of Zürich . They were to become close friends over time.Weyl left Zürich in 1930 to become Hilbert's successor at Göttingen, leaving when the Nazis assumed power in 1933, particularly as his wife was Jewish. The events persuaded him to move to the new

Institute for Advanced Study inPrinceton, New Jersey . He remained there until his retirement in 1951. Together with his wife, he spent his time in Princeton and Zürich, and died in Zürich in 1955.**Contributions****Geometric foundations of manifolds and physics**In 1913, Weyl published "Die Idee der Riemannschen Fläche" ("The Idea of a Riemann Surface"), which gave a unified treatment of

Riemann surface s. In it Weyl utilizedpoint set topology , in order to make Riemann surface theory more rigorous, a model followed in later work onmanifold s. He absorbed L. E. J. Brouwer's early work in topology for this purpose.Weyl, as a major figure in the Göttingen school, was fully apprised of Einstein's work from its early days. He tracked the development of relativity physics in his "Raum, Zeit, Materie" ("Space, Time, Matter") from 1918, reaching a 4th edition in 1922. In 1918, he introduced the notion of gauge, and gave the first example of what is now known as a

gauge theory . Weyl's gauge theory was an unsuccessful attempt to model theelectromagnetic field and thegravitational field as geometrical properties ofspacetime . TheWeyl tensor inRiemannian geometry is of major importance in understanding the nature of conformal geometry. In 1929 Weyl introduced the concept of the vierbein into GR [*1929. "Elektron und Gravitation I", "Zeitshrift Physik", 56, p330-352.*] .His overall approach in physics was based on the phenomenological philosophy of

Edmund Husserl , specifically Husserl's 1913 "Ideen zu einer reinen Phänomenologie und phänomenologischen Philosophie. Erstes Buch: Allgemeine Einführung in die reine Phänomenologie " (Ideas of a Pure Phenomenology and Phenomenological Philosophy. First Book: General Introduction). Apparently this was Weyl's way of dealing with Einstein's controversial dependence on the phenomenological physics of Ernst Mach.Fact|date=August 2008Husserl had reacted strongly to

Gottlob Frege 's criticism of his first work on the philosophy of arithmetic and was investigating the sense of mathematical and other structures, which Frege had distinguished from empirical reference. Hence there is good reason for viewing gauge theory as it developed from Weyl's ideas as a formalism of physical measurement and not a theory of anything physical, i.e. asscientific formalism .Fact|date=August 2008**Topological groups, Lie groups and representation theory**From 1923 to 1938, Weyl developed the theory of

compact group s, in terms ofmatrix representation s. In thecompact Lie group case he proved a fundamental character formula.These results are foundational in understanding the symmetry structure of

quantum mechanics , which he put on a group-theoretic basis. This includedspinor s. Together with themathematical formulation of quantum mechanics , in large measure due toJohn von Neumann , this gave the treatment familiar since about 1930. Non-compact groups and their representations, particularly theHeisenberg group , were also deeply involved. From this time, and certainly much helped by Weyl's expositions, Lie groups andLie algebra s became a mainstream part both ofpure mathematics andtheoretical physics .His book "The Classical Groups", a seminal if difficult text, reconsidered

invariant theory . It coveredsymmetric group s,general linear group s,orthogonal group s, andsymplectic group s and results on theirinvariant s and representations.**Harmonic analysis and analytic number theory**Weyl also showed how to use

exponential sum s indiophantine approximation , with his criterion for uniform distribution mode 1, which was a fundamental step inanalytic number theory . This work applied to theRiemann zeta function , as well asadditive number theory . It was developed by many others.**Foundations of mathematics**In "The Continuum" Weyl developed the logic of predicative analysis using the lower levels of

Bertrand Russell 'sramified theory of types . He was able to develop most of classical calculus, while using neither theaxiom of choice norproof by contradiction , and avoidingGeorge Cantor 'sinfinite set s. Weyl appealed in this period to the radical constructivism of the German romantic, subjective idealistFichte .Shortly after publishing "The Continuum" Weyl briefly shifted his position wholly to the

intuitionism of Brouwer. In "The Continuum", the constructible points exist as discrete entities. Weyl wanted acontinuum that was not an aggregate of points. He wrote a controversial article proclaiming that, for himself and L. E. J. Brouwer, "We are the revolution." This article was far more influential in propagating intuitionistic views than the original works of Brouwer himself.George Pólya and Weyl, during a mathematicians' gathering in Zürich (9 February 1918 ), made abet concerning the future direction of mathematics. Weyl predicted that in the subsequent 20 years, mathematicians would come to realize the total vagueness of notions such asreal number s, sets, and countability, and moreover, that asking about thetruth or falsity of theleast upper bound property of the real numbers was as meaningful as asking about truth of the basic assertions of Georg Hegel on the philosophy of nature. [*Gurevich, Yuri. [*] Any answer to such a question would be unverifiable, unrelated to experience, and therefore senseless.*http://research.microsoft.com/~gurevich/Opera/123.pdf "Platonism, Constructivism and Computer Proofs vs Proofs by Hand"*] , "Bulletin of the European Association of Theoretical Computer Science", 1995. This paper describes a letter discovered by Gurevich in 1995 that documents the bet. It is said that when the friendly bet ended, the individuals gathered cited Pólya as the victor (withKurt Gödel not in concurrence).However, within a few years Weyl decided that Brouwer's intuitionism did put too great restrictions on mathematics, as critics had always said. The "Crisis" article had disturbed Weyl's

formalist teacher Hilbert, but later in the 1920s Weyl partially reconciled his position with that of Hilbert.After about 1928 Weyl had apparently decided that mathematical intuitionism was not compatible with his enthusiasm for the phenomenological philosophy of

Husserl , as he had apparently earlier thought. In the last decades of his life Weyl emphasized mathematics as "symbolic construction" and moved to a position closer not only to Hilbert but to that ofErnst Cassirer . Weyl however rarely refers to Cassirer, and wrote only brief articles and passages articulating this position.**Quotes**Weyl's comment, although half a joke, sums up his personality::My work always tried to unite the truth with the beautiful, but when I had to choose one or the other, I usually chose the beautiful.

:The question for the ultimate foundations and the ultimate meaning of mathematics remains open; we do not know in which direction it will find its final solution nor even whether a final objective answer can be expected at all. "Mathematizing" may well be a creative activity of man, like language or music, of primary originality, whose historical decisions defy complete objective rationalization.:—"Gesammelte Abhandlungen"

:The problems of mathematics are not problems in a vacuum....

:

[ Impredicative definition 's] vicious circle, which has crept into analysis through the foggy nature of the usual set and function concepts, is not a minor, easily avoided form of error in analysis.:In these days the angel of

topology and the devil ofabstract algebra fight for the soul of every individual discipline of mathematics.**Topics named after Hermann Weyl*** See

list of topics named after Hermann Weyl **Notes****References****Primary*** 1913. "Idee der Riemannflāche", 2d 1955. "The Concept of a Riemann Surface". Addison-Wesley.

* 1918. "Das Kontinuum", trans. 1987 "The Continuum : A Critical Examination of the Foundation of Analysis". ISBN 0-486-67982-9

* 1918. " [*http://www.archive.org/details/raumzeitmateriev00weyl Raum, Zeit, Materie*] ". 5 edns. to 1922 ed. with notes by Jūrgen Ehlers, 1980. trans. 4th edn. Henry Brose, 1922 " [*http://www.archive.org/details/spacetimematter00weyluoft Space Time Matter*] ", Methuen, rept. 1952 Dover. ISBN 0-486-60267-2.

* 1923. "Mathematische Analyse des Raumproblems".

* 1924. "Was ist Materie?"

* 1925. (publ. 1988 ed. K. Chandrasekharan) "Riemann's Geometrische Idee".

* 1927. Philosophie der Mathematik und Naturwissenschaft, 2d edn. 1949. "Philosophy of Mathematics and Natural Science". Princeton 0689702078

* 1928. "Gruppentheorie und Quantenmechanik". transl. by H. P. Robertson, "The Theory of Groups and Quantum Mechanics", 1931, rept. 1950 Dover. ISBN 0-486-60269-9

* 1929. "Elektron und Gravitation I", "Zeitschrift Physik", 56, p330-352. - introduction of the vierbein into GR

* 1933. "The Open World" Yale, rept. 1989 Oxbow Press ISBN 0-918024-70-6

* 1934. "Mind and Nature" U. of Pennsylvania Press.

* 1934. "On generalized Riemann matrices," "Ann. of Math. 35": 400–415.

* 1935. "Elementary Theory of Invariants".

* 1939. "Classical Groups: Their Invariants And Representations". Princeton. ISBN 0-691-05756-7

* 1940. "Algebraic Theory of Numbers" rept. 1998 Princeton U. Press. ISBN 0-691-05917-9

* 1952. "Symmetry". Princeton University Press. ISBN 0-691-02374-3

* 1968. in K. Chandrasekharan "ed", "Gesammelte Abhandlungen". Vol IV. Springer.**econdary*** ed. K. Chandrasekharan,"Hermann Weyl, 1885-1985, Centenary lectures delivered by C. N. Yang, R. Penrose, A. Borel, at the ETH Zürich" Springer-Verlag, Berlin, Heidelberg, New York, London, Paris, Tokyo - 1986, published for the Eidgenössische Technische Hochschule, Zürich.

*Deppert, Wolfgang et al., eds., "Exact Sciences and their Philosophical Foundations. Vorträge des Internationalen Herman-Weyl-Kongresses, Kiel 1985", Bern; New York; Paris: Peter Lang 1988,

*Ivor Grattan-Guinness , 2000. "The Search for Mathematical Roots 1870-1940". Princeton Uni. Press.

*Erhard Scholz; Robert Coleman; Herbert Korte; Hubert Goenner; Skuli Sigurdsson; Norbert Straumann eds. "Hermann Weyl's Raum - Zeit - Materie and a General Introduction to his Scientific Work" (Oberwolfach Seminars) (ISBN 3-7643-6476-9) Springer-Verlag New York, New York, N.Y.

*Thomas Hawkins, "Emergence of the Theory of Lie Groups", New York: Springer, 2000.**External links*** [

*http://www.nap.edu/readingroom/books/biomems/hweyl.html National Academy of Sciences biography*]

* [*http://www.nap.edu/readingroom/books/biomems/hweyl.pdf Biography by Atiyah*]

*

* Weisstein, Eric W. " [*http://scienceworld.wolfram.com/biography/Weyl.html Weyl, Hermann*] (1885–1955)". "Eric Weisstein's World of Science".

* Bell, John L. " [*http://publish.uwo.ca/~jbell/Hermann%20Weyl.pdf Hermann Weyl on intuition and the continuum*] "

*Feferman, Solomon. [*http://72.14.209.104/search?q=cache:2aHbpRifP0AJ:math.stanford.edu/~feferman/papers/DasKontinuum.pdf "Significance of Hermann Weyl's das Kontinuum"*]

* Straub, William O. [*http://www.weylmann.com Hermann Weyl Website*]

* Kilmister, C. W. Zeno. "Aristotle, Weyl and Shuard: two-and-a-half millennia of worries over number." 1980

*Persondata

NAME= Weyl, Hermann Klaus Hugo

ALTERNATIVE NAMES=

SHORT DESCRIPTION=German mathematician

DATE OF BIRTH=November 9 ,1885

PLACE OF BIRTH=Elmshorn ,Germany

DATE OF DEATH=December 8 ,1955

PLACE OF DEATH=Zurich ,Switzerland

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