The first proof of the universality of the Feigenbaum constants was carried out by Oscar Lanford—with computer-assistance—in 1982 (with a small correction by Jean-Pierre Eckmann and Peter Wittwer of the University of Geneva in 1987). Over the years, non-numerical methods were discovered for different parts of the proof, aiding Mikhail Lyubich in producing the first complete non-numerical proof.
the first proof of the universality of the feigenbaum constants was carried out by oscar lanford—with computer-assistance—in 1982 (with a small correction by jean-pierre eckmann and peter wittwer of the university of geneva in 1987) over the years non-numerical methods were discovered for different parts of the proof aiding mikhail lyubich in producing the first complete non-numerical proof