G. Comte, ON THE SMOOTHNESS HYPOTHESIS IN SARDS THE OREM ABOUT THE RANK-0 SET, Comptes rendus de l'Academie des sciences. Serie 1, Mathematique, 323(2), 1996, pp. 143-146
In this Note, after remarking that one can improve on the smoothness h
ypotheses stated by Norton and Bates for Sard's theorem about the rank
-0 set, we give a construction showing that the improved hypotheses ar
e the best possible.