Introduction to Graph Pebbling and Rubbling

A graph pebbling move removes two pebbles from a vertex of a graph and adds one pebble to an adjacent vertex. In graph rubbling an additional move is allowed that adds a pebble at a vertex after the removal of one pebble each at two adjacent vertices. A vertex is reachable if a pebble can be moved to the vertex using pebbling/rubbling moves. We study the reachability of vertices under different requirements. After a short introduction to pebbling, the known results about rubbling are summarized.