Published online by Cambridge University Press: 20 November 2018
This article gives a direct proof of Theorem 7.58 of Greiner [4]. This result implies that the classical Mikhlin-Calderón-Zygmund calculus for the principal value convolution operators on ℂ is, in a natural way, the limit of the Laguerre calculus for principal value convolution operators on ℍ1 = ℂ x ℝ.