Nuclei of normal rational curves

Ak-nucleus of a normal rational curve inPG(n, F) is the intersection over allk-dimensional osculating subspaces of the curve (k {–1,0,...,n– 1}). It is well known that for characteristic zero all nuclei are empty. In case of characteristicp}>0 and #Fn the number of non-zero digits in the representation ofn + 1 in basep equals the number of distinct nuclei. An explicit formula for the dimensions ofk-nuclei is given for #F=Fk + 1.Research supported by the Austrian National Science Fund (FWF), project P-12353-MAT.