Ψ

Ψ or ψ may refer to:
*Ordinal collapsing functions
** Weak Buchholz's \(\psi\)
** Bachmann's \(\psi\)
** Madore's \(\psi\)
** Buchholz's \(\psi\)
** Extended Weak Buchholz's \(\psi\)
** Extended Buchholz's \(\psi\)
** Jäger-Buchholz \(\psi\)
** Jäger's \(\psi\)
** Rathjen's \(\psi\)
** Rathjen's \(\Psi\)
** Stegert's \(\Psi\)
*Other notations related to ordinal collapsing functions
**KumaKuma ψ function
*Other notations not related to ordinal collapsing functions
**Psi Notation, a googological notation devised by Antares I.G. Harrison
ja:ψ関数