TESTING INFLATION WITH THE COSMIC MICROWAVE BACKGROUND

Cosmic microwave background (CMB) anisotropy may result from both scal ar and tensor perturbations. For a sufficiently narrow range of angula r scales, CMB perturbations can be characterized by four parameters. R esults from the Cosmic Background Explorer fix one combination of the parameters, reducing the parameters to three. If CMB perturbations are from inflation, there is an additionaL relation, reducing the paramet ers to two. An appropriate combination of a medium-angLe and a small-a ngle CMB observation can test the inflation hypothesis because inflati on cannot explain a high signal in one experiment and a low signal in the other.