The $23$rd letter of the Greek alphabet.
- Minuscule: $\psi$
- Majuscule: $\Psi$
The $\LaTeX$ code for \(\psi\) is
The $\LaTeX$ code for \(\Psi\) is
- $\map \psi x$
The Greek letter $\psi$, along with $\phi$ and $\chi$ and others, is often used to denote a general mapping.
The $\LaTeX$ code for \(\map \psi x\) is
\map \psi x .