This document summarizes several international parity conditions: 1) Purchasing power parity states that identical goods should sell for the same price worldwide when accounting for transportation costs, taxes, and other factors. It is a manifestation of the law of one price applied internationally. 2) Absolute and relative purchasing power parity refer to comparing the price of a standard basket of goods across currencies and changes in inflation affecting exchange rates. 3) Interest rate parity or the Fisher effect relates nominal interest rates, real interest rates, and expected inflation rates both within and between countries. It posits that nominal rates equal real rates plus inflation.