Mammoth Company, through three subsidiaries, controls 87 percent of the equipment to operate central station hazard-detecting devices; these devices are used to prevent burglary and detect fires and to provide electronic notification to police and fire departments at a central location. In an antitrust lawsuit, Mammoth Company claims that there are other means of protecting against burglary and it therefore does not have monopoly power. Explain how the Justice Department may be able to prove its claim that Mammoth Company is operating an illegal monopoly.