Minimal Weak Truth Table Degrees and Computably Enumerable Turing Degrees
A Hierarchy of Turing Degrees
He is also the author or co-author of over 200 research papers, including a highly cited sequence of four papers with Michael Fellows and Karl Abrahamson setting the foundation for the study of parameterised complexity.
Awards and honours
In 1990, Downey won the Hamilton Research Award from the Royal Society of New Zealand In 1992 Downey won the Research Award of the New Zealand Mathematical Society "for penetrating and prolific investigations that have made him a leading expert in many aspects of recursion theory, effective algebra and complexity", New Zealand Mathematical Society, retrieved 19 February 2012. In 1994, he won the New Zealand Association of Scientists Research Award, and became a fellow of the Royal Society of New Zealand in 1996. In 2006, he became the first New Zealand based mathematician to give an Invited Lecture at the International Congress of Mathematicians. He has also given invited lectures at the International Congress of Logic, Methodology and Philosophy of Science and the ACM Conference on Computational Complexity. He was elected as an ACM Fellow in 2007 "for contributions to computability and complexity theory", becoming the second ACM Fellow in New Zealand, and in the same year was elected as a fellow of the New Zealand Mathematical Society. In 2010 he won the Shoenfield Prize of the Association for Symbolic Logic for his work with Denis Hirschfeldt, Andre Nies, and Sebastiaan Terwijn on randomness. In 2011 the Royal Society of New Zealand gave him their Hector Medal "for his outstanding, internationally acclaimed work in recursion theory, computational complexity, and other aspects of mathematical logic and combinatorics." In 2012 he became a fellow of the American Mathematical Society. In 2013, he became a Fellow of the Australian Mathematical Society. In 2014, he was awarded the Nerode Prize from the European Association for Theoretical Computer Science, jointly with Hans Bodlaender, Michael Fellows, Danny Hermelin, Lance Fortnow and Rahul Santhanam for their work on kernelization lower bounds. In October 2016, Downey received a distinguished Humboldt Research Award for his academic contributions. With Denis Hirschfeldt, Downey won another Shoenfield Prize from the Association for Symbolic Logic, this time the 2016 book prize for Algorithmic Randomness and Complexity. In 2018, Downey delivered the Goedel Lecture of the Association for Symbolic Logic in the European Summer Meeting at Udine, Italy. In 2018, Downey was awarded the Rutherford Medal, the highest honour awarded by the Royal Society of New Zealand, "for his pre-eminent revolutionary research into computability, including development of the theory of parameterised complexity and the algorithmic study of randomness."