My complete layman's question. In two of Smolin's books as well as in popular science journals I read that there is the idea of a discrete space, i.e. space would not be completely continuous but rather have "smallest pieces". I wonder if this means that space can be modeled as a graph (the one with nodes and edges, not the plot). The smallest pieces of space would be the nodes of the graph. But what is the neighborhood relation? How many neighbors would every node have? I guess it is not just 6 neighbors like stacked cubes. Harald.