a. Arbitrage is the process of simultaneous purchase or sale of the same financial asset in an attempt to profit by exploiting the price differences on different markets in different forms.
b. Whenever similar assets or a combination of assets are selling for different prices in separate markets, arbitrageurs step in and buy the lower priced asset and sell the higher-priced asset, till the time the price converges.
c. Arbitrage helps in determining prices and establishing the law of one price (i.e. two securities that generate the same cash flows, regardless of future events should have the same price today). They thus help in improving the market efficiency.