Frigyes Riesz ( hu, Riesz Frigyes, , sometimes spelled as Frederic; 22 January 1880 – 28 February 1956) was a
Hungarian[Eberhard Zeidler: Nonlinear Functional Analysis and Its Applications: Linear monotone operators. Springer, 199]
/ref> mathematician
A mathematician is someone who uses an extensive knowledge of mathematics in their work, typically to solve mathematical problems.
Mathematicians are concerned with numbers, data, quantity, structure, space, models, and change.
History
On ...
who made fundamental contributions to functional analysis
Functional analysis is a branch of mathematical analysis, the core of which is formed by the study of vector spaces endowed with some kind of limit-related structure (e.g. Inner product space#Definition, inner product, Norm (mathematics)#Defini ...
, as did his younger brother Marcel Riesz
Marcel Riesz ( hu, Riesz Marcell ; 16 November 1886 – 4 September 1969) was a Hungarian mathematician, known for work on summation methods, potential theory, and other parts of analysis, as well as number theory, partial differential equations ...
.
Life and career
He was born into a Jewish
Jews ( he, יְהוּדִים, , ) or Jewish people are an ethnoreligious group and nation originating from the Israelites Israelite origins and kingdom: "The first act in the long drama of Jewish history is the age of the Israelites""The ...
family in Győr
Győr ( , ; german: Raab, links=no; names of European cities in different languages: E-H#G, names in other languages) is the main city of northwest Hungary, the capital of Győr-Moson-Sopron County and Western Transdanubia, Western Transdanubia ...
, Austria-Hungary
Austria-Hungary, often referred to as the Austro-Hungarian Empire,, the Dual Monarchy, or Austria, was a constitutional monarchy and great power in Central Europe between 1867 and 1918. It was formed with the Austro-Hungarian Compromise of ...
and died in Budapest
Budapest (, ; ) is the capital and most populous city of Hungary. It is the ninth-largest city in the European Union by population within city limits and the second-largest city on the Danube river; the city has an estimated population ...
, Hungary
Hungary ( hu, Magyarország ) is a landlocked country in Central Europe. Spanning of the Carpathian Basin, it is bordered by Slovakia to the north, Ukraine to the northeast, Romania to the east and southeast, Serbia to the south, Croatia a ...
. Between 1911 and 1919 he was a professor at the Franz Joseph University
Royal Hungarian Franz Joseph University ( hu, Magyar Királyi Ferenc József Tudományegyetem) was the second modern university in the Hungarian realm of the Austro-Hungarian Empire. Founded in 1872, its seat was initially in Kolozsvár (Clu ...
in Kolozsvár
; hu, kincses város)
, official_name=Cluj-Napoca
, native_name=
, image_skyline=
, subdivision_type1 = County
, subdivision_name1 = Cluj County
, subdivision_type2 = Status
, subdivision_name2 = County seat
, settlement_type = City
, le ...
, Austria-Hungary. The post-WW1 Treaty of Trianon
The Treaty of Trianon (french: Traité de Trianon, hu, Trianoni békeszerződés, it, Trattato del Trianon) was prepared at the Paris Peace Conference (1919–1920), Paris Peace Conference and was signed in the Grand Trianon château in ...
transferred former Austro-Hungarian territory including Kolozsvár to the Kingdom of Romania
The Kingdom of Romania ( ro, Regatul României) was a constitutional monarchy that existed in Romania from 13 March ( O.S.) / 25 March 1881 with the crowning of prince Karl of Hohenzollern-Sigmaringen as King Carol I (thus beginning the Romanian ...
, whereupon Kolozsvár's name changed to Cluj
; hu, kincses város)
, official_name=Cluj-Napoca
, native_name=
, image_skyline=
, subdivision_type1 = County
, subdivision_name1 = Cluj County
, subdivision_type2 = Status
, subdivision_name2 = County seat
, settlement_type = City
, le ...
and the University of Kolozsvár moved to Szeged
Szeged ( , ; see also #Etymology, other alternative names) is List of cities and towns of Hungary#Largest cities in Hungary, the third largest city of Hungary, the largest city and regional centre of the Southern Great Plain and the county seat ...
, Hungary, becoming the University of Szeged
, mottoeng = Truth. Bravery. Freedom.
, established =
, type = Public research university
, founder = Emperor Franz Joseph I
, affiliation = European University Association, Science Without Borders, Confucius Institute
, budget = US$220 m ...
. Then, Riesz was the rector
Rector (Latin for the member of a vessel's crew who steers) may refer to:
Style or title
*Rector (ecclesiastical), a cleric who functions as an administrative leader in some Christian denominations
*Rector (academia), a senior official in an edu ...
and a professor at the University of Szeged, as well as a member of the Hungarian Academy of Sciences
The Hungarian Academy of Sciences ( hu, Magyar Tudományos Akadémia, MTA) is the most important and prestigious learned society of Hungary. Its seat is at the bank of the Danube in Budapest, between Széchenyi rakpart and Akadémia utca. Its ma ...
. and the Polish Academy of Learning
The Polish Academy of Arts and Sciences or Polish Academy of Learning ( pl, Polska Akademia Umiejętności), headquartered in Kraków and founded in 1872, is one of two institutions in contemporary Poland having the nature of an academy of scien ...
. He was the older brother of the mathematician Marcel Riesz
Marcel Riesz ( hu, Riesz Marcell ; 16 November 1886 – 4 September 1969) was a Hungarian mathematician, known for work on summation methods, potential theory, and other parts of analysis, as well as number theory, partial differential equations ...
.
Riesz did some of the fundamental work in developing functional analysis
Functional analysis is a branch of mathematical analysis, the core of which is formed by the study of vector spaces endowed with some kind of limit-related structure (e.g. Inner product space#Definition, inner product, Norm (mathematics)#Defini ...
and his work has had a number of important applications in physics. He established the spectral theory In mathematics, spectral theory is an inclusive term for theories extending the eigenvector and eigenvalue theory of a single square matrix to a much broader theory of the structure of operators in a variety of mathematical spaces. It is a result ...
for bounded symmetric operators in a form very much like that now regarded as standard. He also made many contributions to other areas including ergodic theory
Ergodic theory (Greek: ' "work", ' "way") is a branch of mathematics that studies statistical properties of deterministic dynamical systems; it is the study of ergodicity. In this context, statistical properties means properties which are expres ...
, topology
In mathematics, topology (from the Greek language, Greek words , and ) is concerned with the properties of a mathematical object, geometric object that are preserved under Continuous function, continuous Deformation theory, deformations, such ...
and he gave an elementary proof of the mean ergodic theorem.
Riesz founded the Acta Scientiarum Mathematicarum
''Acta Scientiarum Mathematicarum'' is a Hungarian mathematical journal published by the János Bolyai Mathematical Institute (University of Szeged). It was established by Alfréd Haar and Frigyes Riesz in 1922. The current editor-in-chief is Lajo ...
journal together with Alfréd Haar
Alfréd Haar ( hu, Haar Alfréd; 11 October 1885, Budapest – 16 March 1933, Szeged) was a Kingdom of Hungary, Hungarian mathematician. In 1904 he began to study at the University of Göttingen. His doctorate was supervised by David Hil ...
.
He had an uncommon method of giving lectures: he entered the lecture hall with an assistant and a docent
The title of docent is conferred by some European universities to denote a specific academic appointment within a set structure of academic ranks at or below the full professor rank, similar to a British readership, a French " ''maître de conf ...
. The docent then began reading the proper passages from Riesz's handbook and the assistant wrote the appropriate equations on the blackboard—while Riesz himself stood aside, nodding occasionally.
The Swiss-American mathematician Edgar Lorch spent 1934 in Szeged working under Riesz and wrote a reminiscence about his time there, including his collaboration with Riesz.
The corpus of his bibliography was compiled by the mathematician Pál Medgyessy
Pál Medgyessy (October 19, 1919, in Egercsehi – October 8, 1977, in Budapest) was a mathematician, Doctor of Mathematical Sciences (1973).
Biography
He graduated at the University of Budapest as a student of Eötvös József Collegium. He star ...
.Pál Medgyessy's entry
in ''Tudósnaptár'' ("Calendar of Scientists")
Publications
*
See also
*
Proximity space
In topology, a proximity space, also called a nearness space, is an axiomatization of the intuitive notion of "nearness" that hold set-to-set, as opposed to the better known point-to-set notion that characterize topological spaces.
The concept was ...
*
Rising sun lemma
*
Denjoy–Riesz theorem
In topology, the Denjoy–Riesz theorem states that every compact set of totally disconnected points in the Euclidean plane can be covered by a continuous image of the unit interval, without self-intersections (a Jordan arc).
Definitions and sta ...
*
F. and M. Riesz theorem
*
Riesz representation theorem
:''This article describes a theorem concerning the dual of a Hilbert space. For the theorems relating linear functionals to measures, see Riesz–Markov–Kakutani representation theorem.''
The Riesz representation theorem, sometimes called the R ...
*
Riesz-Fischer theorem
*
Riesz groups
*
Riesz's lemma
Riesz's lemma (after Frigyes Riesz) is a lemma in functional analysis. It specifies (often easy to check) conditions that guarantee that a subspace in a normed vector space is dense. The lemma may also be called the Riesz lemma or Riesz inequa ...
*
Riesz projector In mathematics, or more specifically in spectral theory, the Riesz projector is the projector onto the eigenspace corresponding to a particular eigenvalue of an operator (or, more generally, a projector onto an invariant subspace corresponding to an ...
*
Riesz sequence In mathematics, a sequence of vectors (''x'n'') in a Hilbert space (H,\langle\cdot,\cdot\rangle) is called a Riesz sequence if there exist constants 0 such that
:
*
Riesz space
In mathematics, a Riesz space, lattice-ordered vector space or vector lattice is a partially ordered vector space where the order structure is a lattice.
Riesz spaces are named after Frigyes Riesz who first defined them in his 1928 paper ''Su ...
*
Radon-Riesz property
References
External links
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{{DEFAULTSORT:Riesz, Frigyes
1880 births
1956 deaths
University of Szeged faculty
19th-century Hungarian mathematicians
20th-century Hungarian mathematicians
Mathematical analysts
Functional analysts
Operator theorists
Mathematicians from Budapest
Members of the Hungarian Academy of Sciences
Burials at Kerepesi Cemetery
Franz Joseph University faculty
Rectors of the Franz Joseph University
Austro-Hungarian mathematicians