# Ronald Jensen

Ronald Björn Jensen (born April 1, 1936) is an American mathematician active in Europe, primarily known for his work in mathematical logic and set theory.

Ronald Jensen
Prof. Ronald Jensen giving a lecture during The First European Set Theory Meeting, Będlewo (Poland), July 2007
BornApril 1, 1936 (age 82)
ResidenceBerlin, Germany
NationalityUnited States
Alma materUniversity of Bonn
Known forSet theory, mathematical logic
Scientific career
FieldsMathematician
InstitutionsHumboldt University of Berlin
Doctoral studentsBenedikt Loewe

## Career

Jensen completed the BA in economics at American University in 1959, and a Ph.D. in mathematics at the University of Bonn in 1964. His supervisor was Gisbert Hasenjaeger. Jensen taught at Rockefeller University, 1969–71, and the University of California, Berkeley, 1971-73. The balance of his academic career was spent in Europe at the University of Bonn, the University of Oslo, the University of Freiburg, the University of Oxford, and the Humboldt-Universität zu Berlin, from which he retired in 2001. He now resides in Berlin.

In 2015 the European Set Theory Society awarded him and John R. Steel the Hausdorff medal for their paper "K without the measurable".

## Results

Jensen's better-known results include the:

## Selected publications

### Articles

• Ronald Jensen, 1969, « On the Consistency of a Slight(?) Modification of Quine's NF », Synthese 19: 250–263. With discussion by Quine. doi:10.1007/BF00568059
• The fine structure of the constructible hierarchy, Annals of Mathematical Logic, vol 4, Issue 3, August 1972, pp. 229–308 doi:10.1016/0003-4843(72)90001-0
• with Anthony J. Dodd: The core model, Annals of Mathematical Logic, vol 20, 1981, pp. 43–75. doi:10.1016/0003-4843(81)90011-5
• with Anthony J. Dodd: The covering lemma for K, Annals of Mathematical Logic, vol 22, 1982, pp. 1–30. doi:10.1016/0003-4843(82)90013-4
• Inner models and large cardinals. Bulletin of Symbolic Logic vol 1, Issue 4 (1995): 393-407. doi:10.2307/421129
• with John R. Steel: K without the measurable, The Journal of Symbolic Logic, vol 78, Issue 3, 2013, pp. 708–734. doi:10.2178/jsl.7803020

### Books

• Modelle der Mengenlehre. Widerspruchsfreiheit und Unabhängigkeit der Kontinuumshypothese und des Auswahlaxioms. (Lecture Notes in Mathematics; vol. 37). Springer, Berlin 1967.
• as editor with Alexander Pestel: Set theory and model theory: proceedings of an informal symposium held at Bonn, June 1–3, 1979. Berlin; New York: Springer-Verlag, 1981.
• with Aaron Beller and Philip Welch: Coding the Universe. Cambridge University Press, Cambridge 1982, ISBN 0-521-28040-0.[1]

## References

1. ^ Mitchell, William J. (1983). "Review: Coding the universe by A. Beller, R. B. Jensen and P. Welch". Bull. Amer. Math. Soc. (N.S.). 8 (2): 350–353. doi:10.1090/s0273-0979-1983-15117-0.