O jisté ploše bikvadratické, jež souvisí s theorií komplexu os rotačních ploch kuželových jdoucích třemi danými body
Here we give several examples of projective degenerations of subvarieties of . The more important case considered here is the d-ple Veronese embedding of ; we will show how to degenerate it to the union of n-dimensional linear subspaces of and the union of scrolls. Other cases considered in this paper are essentially projective bundles over important varieties. The key tool for the degenerations is a general method due to Moishezon. We will give elsewhere several applications to postulation...
The classical Segre theory gives a necessary and sufficient condition for a plane curve to be a branch curve of a (generic) projection of a smooth surface in . We generalize this result for smooth surfaces in a projective space of any dimension in the following way: given two plane curves, and , we give a necessary and sufficient condition for to be the branch curve of a surface in and to be the image of the double curve of a -model of . In the classical Segre theory, a plane curve...