Alexander Sotirios Kechris (; born March 23, 1946) is a

set Set, The Set, SET or SETS may refer to: Science, technology, and mathematics Mathematics *Set (mathematics), a collection of elements *Category of sets, the category whose objects and morphisms are sets and total functions, respectively Electro ...

theorist and

logician Logic is the study of correct reasoning. It includes both formal and informal logic. Formal logic is the study of deductively valid inferences or logical truths. It examines how conclusions follow from premises based on the structure of arg ...

at the

California Institute of Technology The California Institute of Technology (branded as Caltech) is a private research university in Pasadena, California, United States. The university is responsible for many modern scientific advancements and is among a small group of institutes ...

Contributions

Kechris has made contributions to the theory of

Borel equivalence relation In mathematics, a Borel equivalence relation on a Polish space ''X'' is an equivalence relation on ''X'' that is a Borel subset of ''X'' × ''X'' (in the product topology). Given Borel equivalence relations ''E'' and ''F'' on Polish spac ...

s and the theory of

automorphism group In mathematics, the automorphism group of an object ''X'' is the group consisting of automorphisms of ''X'' under composition of morphisms. For example, if ''X'' is a finite-dimensional vector space, then the automorphism group of ''X'' is the g ...

s of

uncountable In mathematics, an uncountable set, informally, is an infinite set that contains too many elements to be countable. The uncountability of a set is closely related to its cardinal number: a set is uncountable if its cardinal number is larger tha ...

structure A structure is an arrangement and organization of interrelated elements in a material object or system, or the object or system so organized. Material structures include man-made objects such as buildings and machines and natural objects such as ...

s. His research interests cover

foundations of mathematics Foundations of mathematics are the mathematical logic, logical and mathematics, mathematical framework that allows the development of mathematics without generating consistency, self-contradictory theories, and to have reliable concepts of theo ...

, mathematical logic and set theory and their interactions with

analysis Analysis (: analyses) is the process of breaking a complex topic or substance into smaller parts in order to gain a better understanding of it. The technique has been applied in the study of mathematics and logic since before Aristotle (38 ...

and

dynamical systems In mathematics, a dynamical system is a system in which a Function (mathematics), function describes the time dependence of a Point (geometry), point in an ambient space, such as in a parametric curve. Examples include the mathematical models ...

. Kechris earned his Ph.D. at UCLA in 1972 under the direction of Yiannis N. Moschovakis, with a dissertation titled '' Projective Ordinals and

Countable In mathematics, a Set (mathematics), set is countable if either it is finite set, finite or it can be made in one to one correspondence with the set of natural numbers. Equivalently, a set is ''countable'' if there exists an injective function fro ...

Analytic Sets''. During his academic career he advised 23 PhD students and sponsored 20

postdoctoral researcher A postdoctoral fellow, postdoctoral researcher, or simply postdoc, is a person professionally conducting research after the completion of their doctoral studies (typically a PhD). Postdocs most commonly, but not always, have a temporary acade ...

s. In 2012, he became an Inaugural Fellow of the

American Mathematical Society The American Mathematical Society (AMS) is an association of professional mathematicians dedicated to the interests of mathematical research and scholarship, and serves the national and international community through its publications, meetings, ...

Honors

*1986 - Invited Speaker at the International Congress of Mathematicians in Berkeley (Mathematical Logic & Foundations) *1998 -

Gödel Lecture The Gödel Lecture is an honor in mathematical logic given by the Association for Symbolic Logic, associated with an annual lecture at the association's general meeting. The award is named after Kurt Gödel and has been given annually since 1990. ...

r (Current Trends in Descriptive Set Theory). *2003 - Received the

Karp Prize The Association for Symbolic Logic (ASL) is an international organization of specialists in mathematical logic and philosophical logic. The ASL was founded in 1936, and its first president was Curt John Ducasse. The current president of the ASL ...

, along with Gregory Hjorth for joint work on Borel equivalence relations, in particular for their results on turbulence and countable

s *2004 - Tarski Lecturer (''New Connections Between Logic, Ramsey Theory and Topological Dynamics'')

Selected publications

* A. S. Kechris, "Classical Descriptive Set Theory", Springer-Verlag, 1995. * H. Becker, A. S. Kechris, "The descriptive set theory of Polish group actions" (London Mathematical Society Lecture Note Series), University of Cambridge, 1996. * A. S. Kechris, V. G. Pestov and S. Todorcevic, "Fraïssé limits, Ramsey theory and topological dynamics of automorphism groups", Geometric and Functional Analysis 15 (1) (2005), 106-189. * A. S. Kechris, "Global Aspects of Ergodic Group Actions", Mathematical Surveys and Monographs, 160, American Mathematical Society, 2010.

References

External links

A. S. Kechris biographical sketch

Kechris's web page at Caltech

American logicians Greek logicians 20th-century Greek mathematicians 21st-century Greek mathematicians California Institute of Technology faculty 1946 births Living people Set theorists Fellows of the American Mathematical Society Philosophers from California {{Greece-mathematician-stub