<Li> Internet connectivity (ISP services) </Li> <Ul> <Li> Electricity </Li> <Li> Telephony </Li> <Li> Airline tickets </Li> </Ul> <P> Perfect substitutability is significant in the era of deregulation, since there are usually several competing providers in a field (e.g. electricity suppliers) each retailing exactly the same product . The result is often aggressive price competition between the retailers . </P> <P> One of the requirements for perfect competition is that the products of competing firms should be perfect substitutes . When this condition is not satisfied, the market is characterized by product differentiation . </P>

If coke price goes up what happens to pepsi demand why