which have continued to form.

In 1969, Nobel Prize-winning economist Thomas Schelling published "Models of Segregation", a paper in which he demonstrated through a "checkerboard model" and mathematical analysis that even when every agent prefers to live in a mixed-race neighborhood, almost complete segregation of neighborhoods emerges as individual decisions accumulate. In his "tipping model", he showed that members of an ethnic group do not move out of a neighborhood as long as the proportion