János Komlós (born 23 May 1942, 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 ...
) is a
Hungarian-American
Hungarian Americans ( Hungarian: ''amerikai magyarok'') are Americans of Hungarian descent. The U.S. Census Bureau has estimated that there are approximately 1.396 million Americans of Hungarian descent as of 2018. The total number of people wit ...
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 ...
, working in
probability theory
Probability theory is the branch of mathematics concerned with probability. Although there are several different probability interpretations, probability theory treats the concept in a rigorous mathematical manner by expressing it through a set o ...
and
discrete mathematics
Discrete mathematics is the study of mathematical structures that can be considered "discrete" (in a way analogous to discrete variables, having a bijection with the set of natural numbers) rather than "continuous" (analogously to continuous f ...
. He has been a professor of
mathematics
Mathematics is an area of knowledge that includes the topics of numbers, formulas and related structures, shapes and the spaces in which they are contained, and quantities and their changes. These topics are represented in modern mathematics ...
at
Rutgers University
Rutgers University (; RU), officially Rutgers, The State University of New Jersey, is a Public university, public land-grant research university consisting of four campuses in New Jersey. Chartered in 1766, Rutgers was originally called Queen's ...
since 1988. He graduated from the
Eötvös Loránd University
Eötvös Loránd University ( hu, Eötvös Loránd Tudományegyetem, ELTE) is a Hungarian public research university based in Budapest. Founded in 1635, ELTE is one of the largest and most prestigious public higher education institutions in Hung ...
, then became a fellow at the
Mathematical Institute 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 ...
. Between 1984–1988 he worked at the
University of California, San Diego
The University of California, San Diego (UC San Diego or colloquially, UCSD) is a public university, public Land-grant university, land-grant research university in San Diego, California. Established in 1960 near the pre-existing Scripps Insti ...
.
Notable results
* He proved that every
L1-bounded sequence of real functions contains a subsequence such that the
arithmetic mean
In mathematics and statistics, the arithmetic mean ( ) or arithmetic average, or just the ''mean'' or the ''average'' (when the context is clear), is the sum of a collection of numbers divided by the count of numbers in the collection. The colle ...
s of all its subsequences
converge pointwise almost everywhere. In probabilistic terminology, the theorem is as follows. Let ξ
1,ξ
2,... be a sequence of
random variable
A random variable (also called random quantity, aleatory variable, or stochastic variable) is a mathematical formalization of a quantity or object which depends on random events. It is a mapping or a function from possible outcomes (e.g., the po ...
s such that ''E''
1">¾1''E''
2">¾2... is bounded. Then there exist a subsequence ξ'
1, ξ'
2,... and a random variable β such that for each further subsequence η
1,η
2,... of ξ'
0, ξ'
1,... we have (η
1+...+η
n)/n → β
a.s.
* With
Miklós Ajtai
Miklós Ajtai (born 2 July 1946) is a computer scientist at the IBM Almaden Research Center, United States. In 2003, he received the Knuth Prize for his numerous contributions to the field, including a classic sorting network algorithm (deve ...
and
Endre Szemerédi
Endre Szemerédi (; born August 21, 1940) is a Hungarian-American mathematician and computer scientist, working in the field of combinatorics and theoretical computer science. He has been the State of New Jersey Professor of computer science a ...
he proved the ''ct''
2/log ''t'' upper bound for the
Ramsey number ''R''(3,''t''). The corresponding lower bound was established by
Jeong Han Kim only in 1995, and this result earned him a
Fulkerson Prize
The Fulkerson Prize for outstanding papers in the area of discrete mathematics is sponsored jointly by the Mathematical Optimization Society (MOS) and the American Mathematical Society (AMS). Up to three awards of $1,500 each are presented at e ...
.
* The same team of authors developed the optimal Ajtai–Komlós–Szemerédi
sorting network
In computer science, comparator networks are abstract devices built up of a fixed number of "wires", carrying values, and comparator modules that connect pairs of wires, swapping the values on the wires if they are not in a desired order. Such net ...
.
* Komlós and Szemerédi proved that if ''G'' is a
random graph
In mathematics, random graph is the general term to refer to probability distributions over graphs. Random graphs may be described simply by a probability distribution, or by a random process which generates them. The theory of random graphs ...
on ''n'' vertices with
:edges, where ''c'' is a fixed real number, then the probability that ''G'' has a
Hamiltonian circuit
In the mathematical field of graph theory, a Hamiltonian path (or traceable path) is a path in an undirected or directed graph that visits each vertex exactly once. A Hamiltonian cycle (or Hamiltonian circuit) is a cycle that visits each vertex ...
converges to
* With
Gábor Sárközy and
Endre Szemerédi
Endre Szemerédi (; born August 21, 1940) is a Hungarian-American mathematician and computer scientist, working in the field of combinatorics and theoretical computer science. He has been the State of New Jersey Professor of computer science a ...
he proved the so-called
blow-up lemma
The blow-up lemma, proved by János Komlós, Gábor N. Sárközy, and Endre Szemerédi in 1997, is an important result in extremal graph theory, particularly within the context of the regularity method. It states that the regular pairs in the s ...
which claims that the regular pairs in
Szemerédi's regularity lemma are similar to
complete bipartite graph
In the mathematical field of graph theory, a complete bipartite graph or biclique is a special kind of bipartite graph where every vertex of the first set is connected to every vertex of the second set..Electronic edition page 17.
Graph theory i ...
s when considering the embedding of graphs with bounded degrees.
* Komlós worked on
Heilbronn's problem; he,
János Pintz
János Pintz (born 20 December 1950 in Budapest) is a Hungary, Hungarian mathematician working in analytic number theory. He is a fellow of the Alfréd Rényi Institute of Mathematics, Rényi Mathematical Institute and is also a member of the Hun ...
and Szemerédi disproved Heilbronn's conjecture.
* Komlós also wrote highly cited papers on sums of random variables, space-efficient representations of sparse sets,
random matrices
In probability theory and mathematical physics, a random matrix is a matrix-valued random variable—that is, a matrix in which some or all elements are random variables. Many important properties of physical systems can be represented mathemat ...
, the
Szemerédi regularity lemma, and
derandomization.
Degrees, awards
Komlós received his Ph.D. in 1967 from
Eötvös Loránd University
Eötvös Loránd University ( hu, Eötvös Loránd Tudományegyetem, ELTE) is a Hungarian public research university based in Budapest. Founded in 1635, ELTE is one of the largest and most prestigious public higher education institutions in Hung ...
under the supervision of
Alfréd Rényi. In 1975 he received the
Alfréd Rényi Prize The Alfréd Rényi Prize is awarded biennially by the Alfréd Rényi Institute of Mathematics of the Hungarian Academy of Science
The Hungarian Academy of Sciences ( hu, Magyar Tudományos Akadémia, MTA) is the most important and prestigious le ...
, a prize established for researchers of the
Alfréd Rényi Institute of Mathematics. In 1998 he was elected as an external member to 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 ...
.
Rutgers Mathematics Department – Recent Faculty Honors
.
See also
* Komlós–Major–Tusnády approximation In probability theory, the Komlós–Major–Tusnády approximation (also known as the KMT approximation, the KMT embedding, or the Hungarian embedding) refers to one of the two strong embedding theorems: 1) approximation of random walk by a standar ...
References
{{DEFAULTSORT:Komlos, Janos
1942 births
Living people
20th-century Hungarian mathematicians
21st-century Hungarian mathematicians
Members of the Hungarian Academy of Sciences
Theoretical computer scientists
Eötvös Loránd University alumni
Rutgers University faculty