Matthias Schulz. How far is to the next recurrent configuration? An NP-complete problem in the sandpile model. In Andrew Adamatzky, Ramón Alonso-Sanz, Anna T. Lawniczak, Genaro Juárez Martínez, Kenichi Morita, Thomas Worsch, editors, Automata 2008: Theory and Applications of Cellular Automata, Bristol, UK, June 12-14, 2008. pages 253-269, Luniver Press, Frome, UK, 2008. [doi]
Abstract is missing.