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...
The dichotomic physical quantities, also called propositions, can be naturally associated to maps of the set of states into the real interval [0,1]. We show that the structure of effect algebra associated to such maps can be represented by quasiring structures, which are a generalization of Boolean rings, in such a way that the ring operation of addition can be non-associative and the ring multiplication non-distributive with respect to addition. By some natural assumption on the effect algebra,...
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.
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