# Seven trees in one

## Idea

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This observation, originally made by Bill Lawvere, has since then been expanded to other ‘’polynomial equations’‘ apart from $T \simeq T^7$ and other types than trees, revealing connections between type theory and calculus.

## References

Revised on March 7, 2013 19:43:06 by Zoran Škoda (161.53.130.104)