Estendendo ricerche di D. Gallarati [2] e di molti altri Autori sul contatto tra due ipersuperficie d'uno spazio proiettivo S lungo una varietà ad r-2 dimensioni, si considera il caso in cui il contatto avvenga lungo le varie falde d'una varietà multipla per le due ipersuperficie.
Let Y be a submanifold of dimension y of a polarized complex manifold (X, A) of dimension k ≥ 2, with 1 ≤ y ≤ k−1. We define and study two positivity conditions on Y in (X, A), called Seshadri A-bigness and (a stronger one) Seshadri A-ampleness. In this way we get a natural generalization of the theory initiated by Paoletti in [Paoletti R., Seshadri positive curves in a smooth projective 3-fold, Atti Accad. Naz. Lincei Cl. Sci. Fis. Mat. Natur. Rend. Lincei (9) Mat. Appl., 1996, 6(4), 259–274] (which...
In the first part of this work (sects. 1-3) we consider an irreducible normal variety of dimension 3 in a complex projective space. Let and be the virtual arithmetic genus and the second arithmetic genus of respectively. We prove that the equality holds if and only if is Cohen-Macaulay. As previously remarked in [11], we obtain the relation for any normal . We also give an example of ’s on which the inequality holds. The problems we treat here are strictly close to some arguments...
We introduce and study the k-jet ampleness and the k-jet spannedness for a vector bundle, E, on a projective manifold. We obtain different characterizations of projective space in terms of such positivity properties for E. We compare the 1-jet ampleness with different notions of very ampleness in the literature.
Page 1