User blog comment:Syst3ms/A formal definition for UNOCF/@comment-35470197-20180728080043/@comment-35392788-20180728092831

I don't see what it matters to know the cofinality of \(\psi_\kappa(\alpha)\). Why not just compute it and then see what its cofinality is ?

Then, what I mean by \(\mapsto\) is a fixed point. For example, \(\alpha \mapsto \psi(\alpha)\) is \(\beta\) such that \(\psi(\beta) = \beta\)

Informally speaking, the diagonalizer rules says "if you find \(\kappa\), then the result is a fixed point of \psi_\kappa".

So, \(\psi_\Omega(\psi_{\Omega_2}(\Omega)) = \alpha \mapsto \psi_\Omega(\psi_{\Omega_2}(\alpha))\)