What is a City? Not a definitive answer but more covering a general history of how cities have been theorized, primarily those in the west.
Comparable to the Polis-City/State of greece for pre industrial cities. Post industrial cities are a different city.
Modernists claim the city is an object of definable place with boundaries. It is a place of knowledge.
Po-Mo’s would say that the city is ever changeable and variable.
The city is an economic system, as Simmel would say it is the seat of the money economy. This market economy generates social conditions of liberty vs solidarity that the city moves between in its built form. Simmel would also say that the city is a psychology and it assumes societal structures as homogeneous.
Community lowers class distinction as well as race distinction. We know where we belong and who we are within that crowd. Able to see the richest of the rich and the poorest of the poor.
The fourth theory is the city as a spatial condition, formalist theories of Edmund Bacon who says there are 5 points of a city
Architecture is to a city as a machine is to a factory.