The Generalized Hypergeometric Structure of the Ward Identities of CFT's in Momentum Space in d>2d > 2

We review the emergence of hypergeometric structures (of $F_4$ Appell functions) from the conformal Ward identities (CWIs) in conformal field theories (CFTs) in dimensions $d > 2$. We illustrate the case of scalar 3- and 4-point functions. 3-point functions are associated to hypergeometric systems with 4 independent solutions. For symmetric correlators they can be expressed in terms of a single 3K integral - functions of quadratic ratios of momenta - which is a parametric integral of three modified Bessel $K$ functions. In the case of scalar 4-point functions, by requiring the correlator to be conformal invariant in coordinate space as well as in some dual variables (i.e. dual conformal invariant), its explicit expression is also given by a 3K integral, or as a linear combination of Appell functions which are now quartic ratios of momenta. Similar expressions have been obtained in the past in the computation of an infinite class of planar ladder (Feynman) diagrams in perturbation theory, which, however, do not share the same (dual conformal/conformal) symmetry of our solutions. We then discuss some hypergeometric functions of 3 variables, which define 8 particular solutions of the CWIs and correspond to Lauricella functions. They can also be combined in terms of 4K integral and appear in an asymptotic description of the scalar 4-point function, in special kinematical limits.Comment: 31 pages, 1 figure. Invited contribution to appear in: Axioms (MDPI) "Geometric Analysis and Mathematical Physics" Ed. Sorin Dragomir, revised final version, typos correcte

Elliptic functions and iterative algorithms for π

Preliminary identities in the theory of basic hypergeometric series, or `q-series\u27, are proven. These include q-analogues of the exponential function, which lead to a fairly simple proof of Jacobi\u27s celebrated triple product identity due to Andrews. The Dedekind eta function is introduced and a few identities of it derived. Euler\u27s pentagonal number theorem is shown as a special case of Ramanujan\u27s theta function and Watson\u27s quintuple product identity is proved in a manner given by Carlitz and Subbarao. The Jacobian theta functions are introduced as special kinds of basic hypergeometric series and various relations between them derived using the triple product identity, among other previously established results. A special quotient of theta functions is introduced as the modular lambda function. The Eisenstein series are first defined through their Lambert series expansions and a series of differential equations due to Ramanujan are developed. Modular forms and functions and subsequently elliptic functions are introduced. The Weierstrass p-function is developed along other elliptic functions, those being defined as certain quotients of theta functions. The first few Eisenstein series are then shown to be expressible in terms of theta functions. Theta functions are shown to be related to Gauss\u27 hypergeometric series _2F_1(a,b;c;z) through the Jacobi inversion theorem. This is shown to have use in relating modular equations and hypergeometric series to pi. The arithmetic-geometric mean iteration of Gauss is developed and used in conjunction with other results established in proofs of two iterative algorithms for pi. Recent applications of pi algorithms using and not using the techniques developed here are then discussed

Convolution properties for certain classes of multivalent functions

AbstractRecently N.E. Cho, O.S. Kwon and H.M. Srivastava [Nak Eun Cho, Oh Sang Kwon, H.M. Srivastava, Inclusion relationships and argument properties for certain subclasses of multivalent functions associated with a family of linear operators, J. Math. Anal. Appl. 292 (2004) 470–483] have introduced the class Sa,cλ(η;p;h) of multivalent analytic functions and have given a number of results. This class has been defined by means of a special linear operator associated with the Gaussian hypergeometric function. In this paper we have extended some of the previous results and have given other properties of this class. We have made use of differential subordinations and properties of convolution in geometric function theory

Ruscheweyh-Goyal Derivative of Fractional Order, its Properties Pertaining to Pre-starlike Type Functions and Applications

The study of the operators possessing convolution form and their properties is considered advantageous in geometric function theory. In 1975 Ruscheweyh defined operator for analytic functions using the technique of convolution. In 2005, Goyal and Goyal generalized the Ruscheweyh operator to fractional order (which we call here Ruscheweyh-Goyal differential operator) using Srivastava-Saigo fractional differential operator involving hypergeometric function. Inspired by these earlier efforts, we discuss the properties of the Ruscheweyh-Goyal derivative of arbitrary order. We define a class of pre-starlike type functions involving the Ruscheweyh-Goyal fractional derivative and obtain the inclusion relation. Further, we prove that Ruscheweyh-Goyal derivative operator preserve the convexity and starlikeness for an analytic function. The majorization results for fractional Ruscheweyh-Goyal derivative has been discussed using a newly defined subclass