MathOverflow will be down for maintenance for approximately 3 hours, starting Monday evening (06/24/2013) at approximately 9:00 PM Eastern time (UTC-4).
3

What grows faster: Busy Beaver function, TREE function or BEAF largest resursive functions (legions, lugions, lagions...)?

flag

closed as off topic by Bugs Bunny, Gjergji Zaimi, Dan Petersen, David Roberts, Bill Johnson Sep 14 at 10:40

1 Answer

4

Much too easy for this site, and already answered. Anyway, BusyBeaver grows faster that any computable function (almost by definition); as the other two are computable... (btw, TREE grows inimaginably faster that the recursive functions you cite next). All these questions tend to show that you have not studied the fast-growing hierarchy : in this notation, Conway's $n\rightarrow n \rightarrow\dots\rightarrow n$ (with $n$ arrows) is (much) smaller than $f_{\omega^2+1}(n)$, and any "recursive" construction in the line of BEAF grows slower than $f_{\omega^\omega}$, while TREE grows much faster than $f_{\epsilon_0}$, or even $f_{\Gamma_0}$...

link|flag
For now, I studied FGH and figured out that TREE(n) surpasses <math>f_{\vartheta(\Omega^\omega)}(n)</math>. – Ikosarakt May 15 at 23:02

Not the answer you're looking for? Browse other questions tagged or ask your own question.