Closed ideals with countable hull in algebras of analytic functions smooth up to the boundary

We denote by T the unit circle and by D the unit disc. Let B be a semi-simple unital commutative Banach algebra of functions holomorphic in D and continuous on D, endowed with the pointwise product. We assume that B is continously imbedded in the disc algebra and satisfies the following conditions: (H1) The space of polynomials is a dense subset of B.(H2) limn→+∞ kz nk1/nB = 1.(H3) There exist k ≥ 0 and C > 0 such that˛˛1 − ˛k‚‚f‚‚B ≤ C‚‚(z − λ)f‚‚B, (f ∈ B, < 2). When B satisfies in addition the analytic Ditkin condition, we give a complete characterisation of closed ideals I of B with countable hull h(I), where h(I) = ˘z ∈ D : f(z) = 0, (f ∈ I)¯.Then, we apply this result to many algebras for which the structure of all closed ideals is unknown. We consider, in particular, the weighted algebras ℓ1(ω) and L1(R+, ω)