Let AP_Sigma^+(R^n) denode the Banach algebra of all continuous
allmost periodic functions on R^n whose Bohr-Fourier
spectrum is contained in an additive semi-group Sigma p[0,infinity)^n .
We show that the maximal ideal space of AP_Sigma^+(R^n)
may have a nonempty corona and we characterize
all Sigma for which the corona is empty. Analogous results are established for algebras of
almost periodic functions with absolutely convergent Fourier series.
Keywords :
Corona Theorem, Almost Periodic Functions, Banach algebra