Random copying is a simple model for population dynamics in the absence of selection, and has been applied to both biological and cultural evolution. In this work, we investigate the effect that spatial structure has on the dynamics. We focus in particular on how a measure of the diversity in the population changes over time. We show that even when the vast majority of a population’s history ma...

A system of algorithms is presented for copying documents that are larger than a normal copier platen. The objective is to produce a single output image by computing the registration between a number of image fragments that are scanned separately but cover the document to be copied. A new method for adjusting the registration of multiple image fragments is proposed in this paper. This technique...

We introduce a growing network model in which a new node attaches to a randomly selected node, as well as to all ancestors of the target node. This mechanism produces a sparse, ultrasmall network where the average node degree grows logarithmically with network size while the network diameter equals 2. We determine basic geometrical network properties, such as the size dependence of the number o...