rule of thumb is that about 20% of the population in each city cannot afford market housing.

the maximum diversity smaller the larger the superlinear scaling of cities,

But in rich ecosystems and among people in cities, it works the other way around: we often obtain greater social freedom (more choice) from being more (selectively and dynamically) connected!

These growth rates will depend on the nation’s variable capacity to learn and the value of its knowledge, as well as some of its natural endowments and institutions.

This is unlike fluctuations in simpler physical systems, which are typically signs of disorder

It is a sort of a “coincidence detector” between the two worldlines in space and time.

will be the main goal for this chapter.

degree,

subject to energy conservation and other constraints.