Arbitrage betting is possible when there is a discrepancy between odds, allowing a profit to be made by covering all outcomes. Usually, this is a bet with just two outcomes, for example in a tennis match, where only two results are possible.
Arbing opportunities most commonly arise when bookmakers disagree on odds, or make a mistake when pricing a market. Sportsbooks and oddsmakers like to be in sync and usually are when it comes to setting lines and odds. Most lines are set by the major sportsbooks, and they are all in constant communication with each other.
Arbing engages a more mathematical approach to ensure profit; most arbers have little or no interest in the sport they are betting on.
Many football betting systems and horse racing strategies are underpinned by the theories associated with arbing.