Orthogonal polynomials with a resolvent-type generating function

On some 2D orthogonal q-polynomials

We introduce two q-analogues of the 2D-Hermite polynomials which are functions of two complex variables. We derive explicit formulas, orthogonality relations, raising and lowering operator relations, generating functions, and Rodrigues formulas for both families. We also introduce a q-2D analogue of the disk polynomials (Zernike polynomials) and derive similar formulas for them as well including evaluating certain connection coefficients. Some of the generating functions may be related to Rogers-Ramanujan type identities.

Generating functions for some series of characters of classical Lie groups

There exist a number of well known multiplicative generating functions for series of Schur functions. Amongst these are some related to the dual Cauchy identity whose expansion coefficients are rather simple, and in some cases periodic in parameters specifying the Schur functions. More recently similar identities have been found involving expansions in terms of characters of the symplectic group. Here these results are extended and generalised to all classical Lie groups. This is done through the derivation of explicit recurrence relations for the expansion coefficients based on the action of …

高斯多项式的正交视角

An Orthogonal View of Gaußian Polynomials

本文为高斯多项式系数引入垂直生成函数，刻画其性质，证明小参数下单峰性，并发现系数差分的意外恒等式及无限同余族。

Hilbert Bases for Orthogonal Arrays

In this paper, we relate the problem of generating all 2-level orthogonal arrays of given dimension and force, i.e. elements in OA$(n,m)$, where $n$ is the number of factors and $m$ the force, to the solution of an Integer Programming problem involving rational convex cones. We do not restrict the number of points in the array, i.e. we admit any number of replications. This problem can be theoretically solved by means of Hilbert bases which form a finite generating set for all the elements in in the infinite set OA$(n,m)$. We discuss some examples which are explicitly solved with a software pe…

块 Pfaffian 的非相交路径解释及其在斜正交多项式中的应用

Non-intersecting path explanation for block Pfaffians and applications into skew-orthogonal polynomials

本文将 Stembridge 的结果推广到块 Pfaffian，用非相交路径给出组合解释，并建立其生成函数与斜正交多项式及多重部分斜正交多项式之间的联系。

More on the O(n) model on random maps via nested loops: loops with bending energy

We continue our investigation of the nested loop approach to the O(n) model on random maps, by extending it to the case where loops may visit faces of arbitrary degree. This allows to express the partition function of the O(n) loop model as a specialization of the multivariate generating function of maps with controlled face degrees, where the face weights are determined by a fixed point condition. We deduce a functional equation for the resolvent of the model, involving some ring generating function describing the immediate vicinity of the loops. When the ring generating function has a single…

离散圆上的预解核与扭曲余割和

The resolvent kernel on the discrete circle and twisted cosecant sums

该研究通过谱展开和商空间两种方法计算离散圆上带特征标扭曲的组合拉普拉斯预解核，利用其唯一性得到余割与正割和的显式计算方法，并推导了循环图L-函数特殊值的递推公式。

A triple lacunary generating function for Hermite polynomials

Some of the classical orthogonal polynomials such as Hermite, Laguerre, Charlier, etc. have been shown to be the generating polynomials for certain combinatorial objects. These combinatorial interpretations are used to prove new identities and generating functions involving these polynomials. In this paper we apply Foata's combinatorial interpretation of the Hermite polynomials as counting matchings of a set to obtain a triple lacunary generating function for the Hermite polynomials. We also give an umbral proof of this generating function.

Cycle indices for finite orthogonal groups of even characteristic

We develop cycle index generating functions for orthogonal groups in even characteristic, and give some enumerative applications. A key step is the determination of the values of the complex linear-Weil characters of the finite symplectic group, and their inductions to the general linear group, at unipotent elements. We also define and study several natural probability measures on integer partitions.

A characterization of ultraspherical, Hermite, and Chebyshev polynomials of the first kind

We show that the only orthogonal polynomials with a generating function of the form $F(x z - αz^2)$ are the ultraspherical, Hermite, and Chebyshev polynomials of the first kind. For special $F$ for which this is the case, we then finish the classification of orthogonal polynomials with more general generating functions $F(x w(z) - R(z))$.

Ratios of Hahn--Exton $q$-Bessel functions and $q$-Lommel polynomials

In 1993 Delest and Fédou showed that a generating function for connected skew shapes is given as a ratio $J_{ν+1}/J_ν$ of the Hahn--Exton $q$-Bessel functions when a parameter $ν$ is zero. They conjectured that when $ν$ is a nonnegative integer the coefficients of the generating function are rational functions whose numerator and denominator are polynomials in $q$ with nonnegative integer coefficients, which is a $q$-analog of Kishore's 1963 result on Bessel functions. The first main result of this paper is a proof of the conjecture of Delest and Fédou. The second main result is a refinement o…

Multiple orthogonal polynomials associated with branched continued fractions for ratios of hypergeometric series

The main objects of the investigation presented in this paper are branched-continued-fraction representations of ratios of contiguous hypergeometric series and type II multiple orthogonal polynomials on the step-line with respect to linear functionals or measures whose moments are ratios of products of Pochhammer symbols. This is an interesting case study of the recently found connection between multiple orthogonal polynomials and branched continued fractions that gives a clear example of how this connection leads to considerable advances on both topics. We obtain new results about generating …