Herbert Kenneth Kunen (born August 2, 1943) is an emeritus professor of mathematics at the University of Wisconsin–Madison who works in set theory and its applications to various areas of mathematics, such as set-theoretic topology and measure theory. He also works on non-associative algebraic systems, such as loops, and uses computer software, such as the Otter theorem prover, to derive theorems in these areas.
Kunen showed that if there exists a nontrivial elementary embedding j:L→L of the constructible universe, then 0# exists. He proved the consistency of a normal, -saturated ideal on from the consistency of the existence of a huge cardinal. He introduced the method of iterated ultrapowers, with which he proved that if is a measurable cardinal with or is a strongly compact cardinal then there is an inner model of set theory with many measurable cardinals. He proved Kunen's inconsistency theorem showing the impossibility of a nontrivial elementary embedding , which had been suggested as a large cardinal assumption (a Reinhardt cardinal).
Away from the area of large cardinals, Kunen is known for intricate forcing and combinatorial constructions. He proved that it is consistent that the Martin Axiom first fails at a singular cardinal and constructed under CH a compact L-space supporting a nonseparable measure. He also showed that has no increasing chain of length in the standard Cohen model where the continuum is .
Selected publications 
- The Foundations of Mathematics. College Publications, 2009. ISBN 978-1-904987-14-7.
- Set Theory: An Introduction to Independence Proofs. North-Holland, 1980. ISBN 0-444-85401-0.
- (co-edited with Jerry E. Vaughan). Handbook of Set-Theoretic Topology. North-Holland, 1984. ISBN 0-444-86580-2.
The journal Topology and its Applications has dedicated a special issue to "Ken" Kunen, containing a biography by Arnold W. Miller, and surveys about Kunen research in various fields by Mary Ellen Rudin, Akihiro Kanamori, István Juhász, Jan van Mill, Dikran Dikranjan, and Michael Kinyon.
- Kenneth Kunen at the Mathematics Genealogy Project
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