Theta functions are special functions of several complex variables. Theta function may also refer to:
Jacobi-related functions q-theta function, , a type of q-series Theta function of a lattice, , a holomorphic function on the upper half-plane Mock theta functions, , etc., a mock modular form of weight 1/2 Ramanujan theta function, Neville theta functions
Other functions Riemann–Siegel theta function, The first Chebyshev function , the sum of the logarithm of all primes Feferman's function, Heaviside step function, sometimes denoted Lovász theta function, an upper bound on the Shannon capacity of a graph
See also Jacobi theta functions (notational variations),