We obtain weighted $L^p$ boundedness, with weights of the type $y^{\delta }$, δ > -1, for the maximal operator of the heat semigroup associated to the Laguerre functions, ${{ℒ}_k^{\alpha }}_k$, when the parameter α is greater than -1. It is proved that when -1 < α < 0, the maximal operator is of strong type (p,p) if p > 1 and 2(1+δ)/(2+α) < p < 2(1+δ)/(-α), and if α ≥ 0 it is of strong type for 1 < p ≤ ∞ and 2(1+δ)/(2+α) < p. The behavior at the end points of the intervals where there is strong type is studied...

Using known results on operator-valued Fourier multipliers on vector-valued function spaces, we give necessary or sufficient conditions for the well-posedness of the second order degenerate equations (P₂): d/dt (Mu’)(t) = Au(t) + f(t) (0 ≤ t ≤ 2π) with periodic boundary conditions u(0) = u(2π), (Mu’)(0) = (Mu’)(2π), in Lebesgue-Bochner spaces $L^p(,X)$, periodic Besov spaces $B_{p,q}^s(,X)$ and periodic Triebel-Lizorkin spaces $F_{p,q}^s(,X)$, where A and M are closed operators in a Banach space X satisfying D(A) ⊂ D(M). Our results...