Hypergeometric function
In mathematics, the Gaussian or ordinary hypergeometric function 2F1(a,b;c;z) is a special function represented by the hypergeometric series, that includes many other special functions as specific or limiting cases. It is a solution of a second-order linear ordinary differential equation (ODE). Every second-order linear ODE with three regular singular points can be transformed into this equation.
The term "hypergeometric function" sometimes refers to the generalized hypergeometric function. For other hypergeometric functions see See also.For systematic lists of some of the many thousands of published identities involving the hypergeometric function, see the reference works by Erdélyi et al. (1953) and Olde Daalhuis (2010). There is no known system for organizing all of the identities; indeed, there is no known algorithm that can generate all identities; a number of different algorithms are known that generate different series of identities. The theory of the algorithmic discovery of identities remains an active research topic.
History[edit]
The term "hypergeometric series" was first used by John Wallis in his 1655 book Arithmetica Infinitorum.
Hypergeometric series were studied by Leonhard Euler, but the first full systematic treatment was given by Carl Friedrich Gauss (1813).
Studies in the nineteenth century included those of Ernst Kummer (1836), and the fundamental characterisation by Bernhard Riemann (1857) of the hypergeometric function by means of the differential equation it satisfies.
Riemann showed that the second-order differential equation for 2F1(z), examined in the complex plane, could be characterised (on the Riemann sphere) by its three regular singularities.
The cases where the solutions are algebraic functions were found by Hermann Schwarz (Schwarz's list).
Integral formulas[edit]
Euler type[edit]
If B is the beta function then
a 2-variable generalization of hypergeometric series
Appell series
where the ratio of terms is a periodic function of the index
Basic hypergeometric series
pHp are similar to generalized hypergeometric series, but summed over all integers
Bilateral hypergeometric series
1F0
Binomial series
1F1(a;c;z)
Confluent hypergeometric series
where the ratio of terms is an elliptic function of the index
Elliptic hypergeometric series
an integral representation of 2F1
Euler hypergeometric integral
an extension of the Meijer G-function
Fox H-function
Frobenius solution to the hypergeometric equation
pFq where the ratio of terms is a rational function of the index
Generalized hypergeometric series
where the ratio of terms is a constant
Geometric series
solutions of second order ODE's with four regular singular points
Heun function
34 distinct convergent hypergeometric series in two variables
Horn function
7 hypergeometric functions of 2 variables
Humbert series
a discrete probability distribution
Hypergeometric distribution
the multivariate generalization of the hypergeometric series
Hypergeometric function of a matrix argument
hypergeometric series of two variables
Kampé de Fériet function
hypergeometric series of three variables
Lauricella hypergeometric series
an extension of the generalized hypergeometric series pFq to the case p>q+1.
MacRobert E-function
an extension of the generalized hypergeometric series pFq to the case p>q+1.
Meijer G-function
a terminating form of the elliptic hypergeometric series
Modular hypergeometric series
a special sort of elliptic hypergeometric series.
Theta hypergeometric series
special functions in two-dimensional conformal field theory that reduce to hypergeometric functions in some cases.
Virasoro conformal blocks
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