2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/131146. Markov chains in time, such as simple random walks, are at the heart of probability. In space, due to the absence of an obvious definition of past and future, a range of definitions of Markovianity have been proposed. In this paper, after a brief review, we introduce a new concept of Markovianity that aims to combine spatial and temporal conditional independence.Published at http://dx.doi.org/10.1214/074921706000000185 in the IMS Lecture Notes--Monograph Series (http://www.imstat.org/publications/lecnotes.htm) by the Institute of Mathematical Statistics (http://www.imstat.org)ProbabilityStatistics Theory60G55, 60D05 (Primary) 62M30 (Secondary)text