GPS meteorology

Psi function can refer, in mathematics, to

• the ordinal collapsing function $\psi (\alpha )$
• the Dedekind psi function $\psi (n)$
• the Chebyshev function $\psi (x)$
• the polygamma function ${\psi }^m(z)$ or its special cases
  • the digamma function $\psi (z)$
  • the trigamma function ${\psi }^1(z)$

and in physics to

• the quantum mechanical wave function.