Начал замечать некоторые тенденции в ученых занятиях чикагских знакомых:
We study a reaction-diffusion system of partial differential equations, which can be taken to be a basic model for criminal activity. We show that the assumption of a populations natural tendency towards crime significantly changes the long-time behavior of criminal activity patterns. Under the right assumptions on these natural tendencies we first show that there exists traveling wave solutions connecting zones with no criminal activity and zones with high criminal activity, known as hotspots. This corresponds to an invasion of criminal activity onto all space. Second, we study the problem of preventing such invasions by employing a finite number of resources that reduce the payoff committing a crime in a finite region. We make the concept of wave propagation mathematically rigorous in this situation by proving the existence of entire solutions that approach traveling waves as time approaches negative infinity. Furthermore, we characterize the minimum amount of resources necessary to prevent the invasion in the case when prevention is possible. Finally, we apply our theory to what is commonly known as the gap problem in the excitable media literature, proving existing conjectures in the literature. http://news.stanford.edu/news/2013/february/crime-math-model-020113.htmlhttp://math.stanford.edu/~ryzhik/brr.pdf
Combining transaction-level data on street prostitutes with ethnographic observation and official police force data, we analyze the economics of prostitution in Chicago. Prostitution, because it is a market, is much more geographically concentrated than other criminal activity. Street prostitutes earn roughly $25-$30 per hour, roughly four times their hourly wage in other activities, but this higher wage represents relatively meager compensation for the significant risk they bear. Prostitution activities are organized very differently across neighborhoods. Where pimps are active, prostitutes appear to do better, with pimps both providing protection and paying efficiency wages. Condoms are used only one-fourth of the time and the price premium for unprotected sex is small. The supply of prostitutes is relatively elastic, as evidenced by the supply response to a 4th of July demand shock. Although technically illegal, punishments are minimal for prostitutes and johns. A prostitute is more likely to have sex with a police officer than to get officially arrested by one. We estimate that there are 4,400 street prostitutes active in Chicago in an average week.http://economics.uchicago.edu/pdf/Prostitution%205.pdf
Говорят: башня из слоновой кости. А бытие-то сильнее!