President Donald Trump on Wednesday awarded the Presidential Medal of Freedom to Arthur Laffer, the father of supply-side economics.

Laffer, 78, was honored for his contributions to economic theory, including the “Laffer Curve,” which holds that tax cuts spur investment, jobs, wages and economic growth.

“I’ve heard and studied the Laffer curve for many years. A very important thing you did, Art,” Trump told him at the White House.