Theta function (disambiguation)

Theta functions $\vartheta (z;\tau )$ are special functions of several complex variables. Theta function may also refer to:

Jacobi-related functions

• q-theta function, $\theta (z;q)$, a type of q-series
• Theta function of a lattice, $\Theta _{\Lambda }(\tau )$, a holomorphic function on the upper half-plane
• Mock theta functions, $\mu (q),f(q),\phi (q),\psi (q),\chi (q)$, etc., a mock modular form of weight 1/2
• Ramanujan theta function, $f(a,b)$
• Neville theta functions

Other functions

• Riemann–Siegel theta function, $\theta (t)$
• The first Chebyshev function $\vartheta (x)$, the sum of the logarithm of all primes $\leq x$
• Feferman's function, $\theta _{\alpha }(\beta )$
• Heaviside step function, sometimes denoted $\theta (x)$
• Lovász theta function, an upper bound on the Shannon capacity of a graph

See also

• Jacobi theta functions (notational variations), $\vartheta _{ij}(z;\tau ),\vartheta _{j}(z),\theta _{i}(z;q)$