Many products--including microprocessors, telecommunications devices, computer software, and on-line auction services--make use of multiple technologies, each of which is essential to make or sell the product. The owner of one technology benefits from the existence of complementary technologies....

Public and private entities around the world are trying to induce the provision of higher-quality health care by adopting institutional arrangements intended to promote competition among care providers. I selectively survey and supplement the literature to show that an increase in...