\documentclass[12pt,reqno]{article} \usepackage[usenames]{color} \usepackage{amssymb} \usepackage{graphicx} \usepackage{amscd} \usepackage[colorlinks=true, linkcolor=webgreen, filecolor=webbrown, citecolor=webgreen]{hyperref} \definecolor{webgreen}{rgb}{0,.5,0} \definecolor{webbrown}{rgb}{.6,0,0} \usepackage{color} \usepackage{fullpage} \usepackage{float} \usepackage{psfig} \usepackage{graphics,amsmath,amssymb} \usepackage{amsthm} \usepackage{amsfonts} \usepackage{latexsym} \usepackage{epsf} \setlength{\textwidth}{6.5in} \setlength{\oddsidemargin}{.1in} \setlength{\evensidemargin}{.1in} \setlength{\topmargin}{-.1in} \setlength{\textheight}{8.4in} \newcommand{\seqnum}[1]{\href{http://oeis.org/#1}{\underline{#1}}} \newcommand{\fstirling}[2]{\genfrac[]{0pt}{}{#1}{#2}} \newcommand{\sstirling}[2]{\genfrac\{\}{0pt}{}{#1}{#2}} \begin{document} \begin{center} \epsfxsize=4in \leavevmode\epsffile{logo129.eps} \end{center} \theoremstyle{plain} \newtheorem{theorem}{Theorem} \newtheorem{corollary}[theorem]{Corollary} \newtheorem{lemma}[theorem]{Lemma} \newtheorem{proposition}[theorem]{Proposition} \theoremstyle{definition} \newtheorem{definition}[theorem]{Definition} \newtheorem{example}[theorem]{Example} \newtheorem{conjecture}[theorem]{Conjecture} \theoremstyle{remark} \newtheorem{remark}[theorem]{Remark} \newtheorem{problem}[theorem]{Problem} \begin{center} \vskip 1cm{\LARGE\bf Some Theorems and Applications of the\\ \vskip .1in $(q,r)$-Whitney Numbers} \vskip 1cm \large Mahid M. Mangontarum\\ Department of Mathematics\\ Mindanao State University---Main Campus\\ Marawi City 9700\\ Philippines \\ \href{mailto:mmangontarum@yahoo.com}{\tt mmangontarum@yahoo.com} \\ \href{mailto:mangontarum.mahid@msumain.edu.ph}{\tt mangontarum.mahid@msumain.edu.ph} \\ \end{center} \vskip .2 in \begin{abstract} The $(q,r)$-Whitney numbers were recently defined in terms of the $q$-Boson operators, and several combinatorial properties which appear to be $q$-analogues of similar properties were studied. In this paper, we obtain elementary and complete symmetric polynomial forms for the $(q,r)$-Whitney numbers, and give combinatorial interpretations in the context of $A$-tableaux. We also obtain convolution-type identities using the combinatorics of $A$-tableaux. Lastly, we present applications and theorems related to discrete $q$-distributions. \end{abstract} \section{Introduction} \label{sec:Introduction} In a recent paper, the author and Katriel \cite{Mah2} introduced a new approach to generate $q$-analogues of Stirling and Whitney-type numbers. In this paper, the $(q,r)$-Whitney numbers of the first and second kinds were defined as coefficients in \begin{equation} m^n(a^\dagger)^n a^n=\sum_{k=0}^{n}w_{m,r,q}(n,k)(ma^\dagger a+r)^k\label{qw1} \end{equation} and \begin{equation} (ma^\dagger a+r)^n=\sum_{k=0}^{n}m^kW_{m,r,q}(n,k)(a^\dagger)^k a^k,\label{qw2} \end{equation} respectively (cf.\ \cite{Mah2}), by using as framework, the $q$-Boson operators $a^{\dagger}$ and $a$ of Arik and Coon \cite{Arik} which satisfy the commutation relation \begin{equation} [a,a^\dagger]_q\equiv aa^\dagger-qa^\dagger a=1.\label{qbos} \end{equation} By convention, $w_{m,r,q}(0,0)=W_{m,r,q}(0,0)=1$ and $w_{m,r,q}(n,k)=W_{m,r,q}(n,k)=0$ for $k>n$ and for $k<0$. Several combinatorial properties were already established, including the following triangular recurrence relations \cite[Theorem\ 6]{Mah2}: \begin{equation} w_{m,r,q}(n+1,k)=q^{-n}\Big(w_{m,r,q}(n,k-1)-(m[n]_q+r)w_{m,r,q}(n,k)\Big), \label{identity4} \end{equation} with $[n]_q=\frac{q^n-1}{q-1}$, the $q$-integer, and \begin{equation} W_{m,r,q}(n+1,k)=q^{k-1}W_{m,r,q}(n,k-1)+(m[k]_q+r)W_{m,r,q}(n,k).\label{identity5} \end{equation} From here, one readily obtains \begin{equation} w_{m,r,q}(n,0)=(-1)^nq^{-\binom{n}{2}}\prod_{i=0}^{n-1}(m[i]_q+r),\label{w0} \end{equation} \begin{equation} w_{m,r,q}(n,n)=q^{-\binom{n}{2}},\label{wn} \end{equation} \begin{equation} W_{m,r,q}(n,0)=r^n,\label{W0} \end{equation} and \begin{equation} W_{m,r,q}(n,n)=q^{\binom{n}{2}}.\label{Wn} \end{equation} The identities presented in Eqs.~\eqref{identity4} and \eqref{identity5} can be used as tools to obtain further combinatorial identities for $w_{m,r,q}(n,k)$ and $W_{m,r,q}(n,k)$. For instance, with the aid of these recurrence relations, the vertical recurrence relations \begin{equation} w_{m,r,q}(n+1,k+1)=\sum_{j=k}^{n}(-1)^{n-j}q^{\binom{j}{2}-\binom{n+1}{2}}w_{m,r,q}(j,k)\prod_{i=j+1}^n(m[i]_q+r),\label{vertrec1} \end{equation} with $\prod_{i=j+1}^n(m[i]_q+r)=1$ when $j=n$, and \begin{equation} W_{m,r,q}(n+1,k+1)=q^k\sum_{j=k}^{n}(m[k+1]_q+r)^{n-j}W_{m,r,q}(j,k),\label{vertrec2} \end{equation} can be proved by induction, as well as the rational generating function of the $(q,r)$-Whitney numbers of the second kind given by \begin{equation} \sum_{n=k}^{\infty}W_{m,r,q}(n,k)t^n=\frac{q^{\binom{k}{2}}t^k}{\prod_{i=0}^k\left(1-(m[i]_q+r)t\right)}.\label{ratgenf} \end{equation} On the other hand, the horizontal recurrence relations \begin{equation} w_{m,r,q}(n,k)=q^n\sum_{j=0}^{n-k}(m[n]_q+r)^jw_{m,r,q}(n+1,k+j+1)\label{horrec1} \end{equation} and \begin{equation} W_{m,r,q}(n,k)=\sum_{j=0}^{n-k}(-1)^{j}q^{\binom{k}{2}-\binom{k+j+1}{2}}\frac{\prod_{i=0}^{k+j}(m[i]_q+r)}{\prod_{i=0}^{k}(m[i]_q+r)}W_{m,r,q}(n+1,k+j+1)\label{horrec2} \end{equation} can be verified by evaluating the right-hand sides using Eqs.~\eqref{identity4} and \eqref{identity5}. Before proceeding, we note that Eqs.~\eqref{vertrec1} and \eqref{vertrec2} follow a behaviour similar to that of the Chu-Shi-Chieh's identity (see \cite{Chen}) for the classical binomial coefficients given by \begin{equation*} \binom{n+1}{k+1}=\binom{k}{k}+\binom{k+1}{k}+\cdots+\binom{n}{k}, \end{equation*} while Eqs.~\eqref{horrec1} and \eqref{horrec2} are analogous with \begin{equation*} \binom{n}{k}=\binom{n+1}{k+1}-\binom{n+1}{k+2}+\cdots+(-1)^{n-k}\binom{n+1}{n+1}, \end{equation*} another known identity for the classical binomial coefficients. The purpose of this paper is to express the $(q,r)$-Whitney numbers of both kinds in symmetric polynomial forms. This proves to be useful in establishing combinatorial interpretations in terms of $A$-tableaux. In return, remarkable convolution-type identities are obtained and several other interesting theorems are also presented. \section{Explicit formulas in symmetric polynomial forms} \subsection{$(q,r)$-Whitney numbers of the first kind} Expanding the falling factorial $(x)_{n}=x(x-1)\cdots(x-n+1)$ in powers of $x$, we obtain $$(x)_{n}=\sum_{k=0}^n (-1)^{n-k}x^k \sum_{1\leq i_1