(G,m)-multiparking functions

Abstract

The conceptions of $G$-parking functions and $G$-multiparking functions were introduced in [15] and [12] respectively. In this paper, let $G$ be a connected graph with vertex set $\{1,2,...,n\}$ and $m\in V(G)$. We give the definition of $(G,m)$-multiparking function. This definition unifies the conceptions of $G$-parking function and $G$-multiparking function. We construct bijections between the set of $(G,m)$-multiparking functions and the set of $\mathcal{F}_{G,m}$ of spanning color $m$-forests of $G$. Furthermore we define the $(G,m)$-multiparking complement function, give the reciprocity theorem for $(G,m)$-multiparking function and extend the results [25,12] to $(G,m)$-multiparking function. Finally, we use a combinatorial methods to give a recursion of the generating function of the sum $\sum\limits_{i=1}^na_i$ of $G$-parking functions $(a_1,...,a_n)$.