2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/74724We explore the complexity of computing the optimal pebbling number and pebbling number of a graph. We show that deciding whether the optimal pebbling number of G is at most k is NP-complete and deciding whether the pebbling number of G is at most k is Π_2-complete. Additionally, we provide a characterization of when an unordered set of pebbling moves can be ordered to form a valid sequence of pebbling moves.24 pages, 6 figuresCombinatorics05C99, 68Q17text