"Many thanks for posting this one picture tutorial. It led me to find Thomas Royen's elegant proof of the Gaussian Correlation Inequality, and a nice article in Quanta Magazine -
A Long-Sought Proof, Found and Almost Lost"
Education in mathematics. 30 years a systems programmer and software engineer: device drivers, to natural language processing, to business systems. Now combining math & programming + dash of computational linguistics & Python to re-brand as a data scientist.