Bouncing Cosmology made simple
  We introduce the "wedge diagram," an intuitive way to illustrate how
cosmological models with a classical (non-singular) bounce generically resolve
fundamental problems in cosmology. These include the well-known horizon,
flatness, and inhomogeneity problems; the small tensor-to-scalar ratio observed
in the cosmic microwave background; the low entropy at the beginning of a hot,
expanding phase; and the avoidance of quantum runaway. The same diagrammatic
approach can be used to compare with other cosmological scenarios.
