Ronald Jensen

Career

Results

• Axiomatic set theory NFU, a variant of New Foundations where extensionality is weakened to allow several sets with no elements, and the proof of NFU's consistency relative to Peano arithmetic;
• Fine structure theory of the constructible universe L. This work led to his being awarded in 2003 the Leroy P. Steele Prize for Seminal Contribution to Research of the American Mathematical Society for his 1972 paper titled "The fine structure of the constructible hierarchy";
• Definitions and proofs of various infinitary combinatorial principles in L, including diamond, square, and morass;
• Jensen's covering theorem for L;
• General theory of core models and the construction of the Dodd–Jensen core model;
• Consistency of CH plus Suslin's hypothesis.
• Technique of coding the universe by a real.

  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.
• The fine structure of the constructible hierarchy, Annals of Mathematical Logic, vol 4, Issue 3, August 1972, pp. 229–308
• with Anthony J. Dodd: The core model, Annals of Mathematical Logic, vol 20, 1981, pp. 43–75.
• with Anthony J. Dodd: The covering lemma for K, Annals of Mathematical Logic, vol 22, 1982, pp. 1–30.
• Inner models and large cardinals. Bulletin of Symbolic Logic vol 1, Issue 4 : 393-407.
• with John R. Steel: K without the measurable, The Journal of Symbolic Logic, vol 78, Issue 3, 2013, pp. 708–734.

  Books

• Modelle der Mengenlehre. Widerspruchsfreiheit und Unabhängigkeit der Kontinuumshypothese und des Auswahlaxioms.. 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: Cambridge University Press, Cambridge 1982,.