Pointwise Fourier inversion - An addendum

In this note we complete a circle of results presented in 5 of an earlier w ork of the author (J. Fourier Anal. 5 (1999), 449-463), establishing the en dpoint case of Proposition 10 of that paper. As a consequence, we have resu lts on pointwise convergence of the Fourier series (summed by spheres) of a function on the 3-dimensional torus with a simple jump across a smooth sur face Sigma, with no curvature hypotheses on Sigma, extending Proposition 7 of that paper.