Timeline for Göbel's correspondance between rooted trees and natural numbers
Current License: CC BY-SA 4.0
7 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Jun 6, 2021 at 3:09 | comment | added | Arya McCarthy | Chiming in just to indicate that Göbel discovered this in 1980, independently of David Matula who discovered this in 1968. The natural number for a given rooted tree is often called the Matula number. | |
| Jun 6, 2021 at 2:28 | history | became hot network question | |||
| Jun 5, 2021 at 21:03 | vote | accept | Mario Krenn | ||
| Jun 5, 2021 at 19:41 | answer | added | Benjamin Dickman | timeline score: 15 | |
| Jun 5, 2021 at 18:45 | comment | added | Asvin | So the pattern seems to be that if $p$ is the n-th prime, then you attach the graph associated to $n$. It seems very plausible to me that this will indeed give a bijection. | |
| Jun 5, 2021 at 18:44 | comment | added | Asvin | Certainly one obvious pattern is that for the prime numbers $p$, there is exactly one vertex adjacent to the root. If we remove the root, we get another tree associated to some $n < p$. In the examples above, we get the pairs $(p,n)$ equal to $3 - 2, 5 - 3, 7 - 4, 11 - 5, 13 - 6, 17 - 7, 19 - 8, 23 - 9, 29- 10...$ | |
| Jun 5, 2021 at 18:24 | history | asked | Mario Krenn | CC BY-SA 4.0 |