cantors-attic

Climb into Cantor’s Attic, where you will find infinities large and small. We aim to provide a comprehensive resource of information about all notions of mathematical infinity.

View the Project on GitHub neugierde/cantors-attic

Quick navigation
The upper attic
The middle attic
The lower attic
The parlour
The playroom
The library
The cellar

Sources
Cantor's Attic (original site)
Joel David Hamkins blog post about the Attic
Latest working snapshot at the wayback machine

Extended Veblen function

The Extended Veblen function is a function with more than 2 arguments to express ordinals from \(\Gamma_0\) to \(\psi(\Omega^{\Omega^\omega})\), the small Veblen ordinal.

Definition

\(\varphi(1,0,0)=\varphi_{\varphi_{\ddots_{\varphi_0(0)}}(0)}(0) \
\varphi(1,0,1)=\varphi_{\varphi_{\ddots_{\varphi(1,0,0)+1}}(0)}(0) \
\varphi(1,0,n+1)=\varphi_{\varphi_{\ddots_{\varphi(1,0,n)+1}}(0)}(0) \\ \varphi(1,1,0)=\varphi(1,0,\varphi(1,0,\varphi(1,0,\cdots))) \
\varphi(1,1,1)=\varphi_{\varphi_{\ddots_{\varphi(1,1,0)+1}}(0)}(0) \\ \varphi(1,2,0)=\varphi(1,1,\varphi(1,1,\varphi(1,1,\cdots))) \\ \varphi(1,n+1,0)=\varphi(1,n,\varphi(1,n,\varphi(1,n,\cdots))) \\ \varphi(2,0,0)=\varphi(1,\varphi(1,\varphi(1,\cdots,0),0),0) \
\varphi(2,0,1)=\varphi_{\varphi_{\ddots_{\varphi(2,0,0)+1}}(0)}(0) \\ \varphi(2,1,0)=\varphi(2,0,\varphi(2,0,\varphi(2,0,\cdots))) \\ \varphi(3,0,0)=\varphi(2,\varphi(2,\varphi(2,\cdots,0),0),0) \\ \varphi(n+1,0,0)=\varphi(n,\varphi(n,\varphi(n,\cdots,0),0),0) \
\varphi(1,0,0,0)=\varphi(\varphi(\varphi(\cdots,0,0),0,0),0,0)\)