User blog comment:Deedlit11/Ordinal Notations IV: Up to a weakly inaccessible cardinal/@comment-7484840-20130709093331

Why would $$\psi_{\Omega_{I+1}}(0) =\Gamma_{I+1}$$? In the psi function, psi(0) = epsilon_0. If I am wrong, (which is highly possible) then how does $$\psi_{\Omega_{I+1}}(0)$$ work?