Cosmic-ray observations and dark matter

The inflationary model of the Universe predicts a density parameter Omega=1. Present dark matter observations do not support this assumption. It is shown that the study of cosmic rays might help to clarify the role played by the major components of dark matter in the Universe. In particular, it is pointed out that positron-to-electron ratio observations above 10 GeV with errors smaller than 30% could give precious hints about supersymmetric particle annihilation in the galactic halo.