Theta function (disambiguation)

Theta function can refer to functions related to Jacobi's theta functions:

• the Jacobi theta function $\vartheta (z;\tau )$
  • Jacobi theta functions (notational variations) $\vartheta _{ij}(z;\tau ),\vartheta _{j}(z),\theta _{i}(z;q)$
• the q-theta function $\theta (z;q)$
• the theta function of a lattice $\Theta _{\Lambda }(\tau )$
• the Riemann theta function $\vartheta (z;\tau )$ on $\mathbb {H} _{n}$
• Ramanujan's mock theta functions $\mu (q),f(q),\phi (q),\psi (q),\chi (q)$, etc.
• the Ramanujan theta function $f(a,b)$

Other unrelated functions called theta functions include:

• the Riemann–Siegel theta function $\theta (t)$ in analysis
• the Chebyshev function $\vartheta (x)$ in number theory
• Feferman's function $\theta _{\alpha }(\beta )$ in set theory