Ability to exchange one currency for another at a given conversion rate and in terms of the usability of a currency for foreign transactions

Which states that exchange rates between currencies are in equilibrium when their purchasing power is the same in each of the two countries

When one party of an economic transaction has equal degree of information in currency market about it and shared equally to arrive at uniform foreign exchange selection decision

No one party can significantly influence foreign exchange rate in the market and all will be guided by asymmetric information