2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/68142For a directed graph G on vertices {0,1,...,n}, a G-parking function is an n-tuple (b_1,...,b_n) of non-negative integers such that, for every non-empty subset U of {1,...,n}, there exists a vertex j in U for which there are more than b_j edges going from j to G-U. We construct a family of bijective maps between the set P_G of G-parking functions and the set T_G of spanning trees of G rooted at 0, thus providing a combinatorial proof of |P_G| = |T_G|.11 pages, 4 figures; a family of bijections containing the two original bijections is presented; submitted to J. Combinatorial Theory, Series ACombinatorics05A99; 05C05text