Bjarni Jónsson (February 15, 1920 – September 30, 2016) was an Icelandic

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 ...

and

logician Logic is the study of correct reasoning. It includes both formal and informal logic. Formal logic is the science of deductively valid inferences or of logical truths. It is a formal science investigating how conclusions follow from premises ...

working in

universal algebra Universal algebra (sometimes called general algebra) is the field of mathematics that studies algebraic structures themselves, not examples ("models") of algebraic structures. For instance, rather than take particular groups as the object of study, ...

lattice theory A lattice is an abstract structure studied in the mathematical subdisciplines of order theory and abstract algebra. It consists of a partially ordered set in which every pair of elements has a unique supremum (also called a least upper boun ...

model theory In mathematical logic, model theory is the study of the relationship between formal theories (a collection of sentences in a formal language expressing statements about a mathematical structure), and their models (those structures in which the s ...

and

set theory Set theory is the branch of mathematical logic that studies sets, which can be informally described as collections of objects. Although objects of any kind can be collected into a set, set theory, as a branch of mathematics, is mostly conce ...

. He was

emeritus ''Emeritus'' (; female: ''emerita'') is an adjective used to designate a retired chair, professor, pastor, bishop, pope, director, president, prime minister, rabbi, emperor, or other person who has been "permitted to retain as an honorary title ...

distinguished professor Distinguished Professor is an academic title given to some top tenured professors in a university, school, or department. Some distinguished professors may have endowed chairs. In the United States Often specific to one institution, titles such ...

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 ...

Vanderbilt University Vanderbilt University (informally Vandy or VU) is a private research university in Nashville, Tennessee. Founded in 1873, it was named in honor of shipping and rail magnate Cornelius Vanderbilt, who provided the school its initial $1-million ...

and the honorary editor in chief of ''

Algebra Universalis ''Algebra Universalis'' is an international scientific journal focused on universal algebra and lattice theory. The journal, founded in 1971 by George Grätzer, is currently published by Springer-Verlag. Honorary editors in chief of the journal ...

''. He received his PhD in 1946 at

UC Berkeley The University of California, Berkeley (UC Berkeley, Berkeley, Cal, or California) is a public university, public land-grant university, land-grant research university in Berkeley, California. Established in 1868 as the University of Californi ...

under supervision of

Alfred Tarski Alfred Tarski (, born Alfred Teitelbaum;School of Mathematics and Statistics, University of St Andrews ''School of Mathematics and Statistics, University of St Andrews''. January 14, 1901 – October 26, 1983) was a Polish-American logician a ...

. In 2012, he became a 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, ...

.List of Fellows of the American Mathematical Society
retrieved 2013-01-26.

Work

Jónsson's lemma as well as several mathematical objects are named after him, among them

Jónsson algebra Jónsson is a surname of Icelandic origin, meaning ''son of Jón''. In Icelandic names, the name is not strictly a surname, but a patronymic. The name refers to: * Arnar Jónsson (actor) (born 1943), Icelandic actor * Arnar Jónsson (basketball) (bo ...

s, ω- Jónsson functions,

Jónsson cardinal In set theory, a Jónsson cardinal (named after Bjarni Jónsson) is a certain kind of large cardinal number. An uncountable cardinal number κ is said to be ''Jónsson'' if for every function ''f'': �sup><ω → κ there is a set ''H'' of or ...

Jónsson term In universal algebra, within mathematics, a majority term, sometimes called a Jónsson term, is a term (logic), term ''t'' with exactly three free variables that satisfies the equations ''t''(''x'', ''x'', ''y'') = ''t''(''x'', ''y'', ''x'') = ''t'' ...

Jónsson–Tarski algebra In mathematics, a Jónsson–Tarski algebra or Cantor algebra is an algebraic structure encoding a bijection from an infinite set onto the Cartesian product, product . They were introduced by . , named them after Georg Cantor because of Cantor's ...

s and Jónsson–Tarski duality.

Publications

References

External links

Bjarni Jónsson's homepage
1920 births Bjarni Jonsson Algebraists Lattice theorists 20th-century mathematicians University of California, Berkeley alumni Vanderbilt University faculty Fellows of the American Mathematical Society Bjarni Jonsson 2016 deaths {{Iceland-scientist-stub Brown University faculty Icelandic expatriates in the United States

Work

Publications

References

Further reading

External links