  Using semiclassical approximation method, Bose-Einstein condensation (BEC) of
a relativistic ideal boson gas (RIBG) with and without antibosons in
three-dimensional (3-D) harmonic traps is investigated. The BEC transition
temperature T_{c} and the Helmholtz free energy at T_{c} are calculated. The
effect of the rest mass of the boson on the properties of the system is also
studied. We find that T_{c} of RIBG is higher than that of the nonrelativistic
approximation. The RIBG with antibosons is also investigated and it is found
that the Helmholtz free energy of the system with antibosons at T_{c} is lower
than that of the system without antibosons. It implies that the system with
antibosons is more stable.
