Prompt and direct muon production in the atmosphere and very high energy inclined EAS at sea level

Prompt muons are produced through decays of charmed particles and direct muons are produced through decays of particles with life-time much less than that of charmed particles (for example, resonances). The ratios of the number of particles in showers initiated by bremsstrahlung of these muons to those from decays of π° - mesons from primary nucleon interactions in the atmosphere are estimated for the primary nucleon energy 1019 eV. The calculations are made at θ∼45°−72° to the vertical at sea level. At large angles prompt and direct muons could be completely responsible for EAS measured at the sea level.