There is a natural bijection between the set of finite binary trees and the set of seven-tuples of such.
This observation, originally made by Bill Lawvere, has since then been expanded to other “polynomial equations” apart from and other types than trees, revealing connections between type theory and calculus.
John Baez, this week’s finds in mathematical physics, week 202, web
Andreas Blass, seven trees in one, arXiv:math/9405205v1
Tom Leinster, objects of categories as complex numbers, arXiv:math/0212377v1
Last revised on June 1, 2021 at 16:14:21. See the history of this page for a list of all contributions to it.