ALASTAIR GRANT/The Associated Press Robert A. Mundell, a Nobel Prize-winning economist whose theorizing opened the door to understanding the workings of global finance and the modern-day international economy, while his more iconoclastic views on economic policy fostered the creation of the euro and the adoption of the tax-cutting approach known as supply-side economics, died Sunday at his home, a Renaissance-era palazzo that he and his wife restored, near Siena, Italy. He was 88. The cause was cholangiocarcinoma, cancer of the bile duct, said his wife, Valerie Natsios-Mundell. Mr. Mundell, a Canadian who taught at the University of Chicago and Columbia University, among other places, was awarded the Nobel Memorial Prize in Economic Sciences in 1999 “for his analysis of monetary and fiscal policy under different exchange rate regimes and his analysis of optimum currency areas.”