The article looks at how inflation in the US has behaved recently. They use a simple equation that says inflation depends on how much people expect prices to rise and how many people are looking for work. This equation explains why high unemployment after 2008 didn't lower inflation much. When they use a different measure of inflation, the equation works even better. They also have a more general equation that says inflation depends on how many people are looking for work and what people expect prices to do in the future. This equation works for US inflation since 1985, including times when people's expectations about prices were different.