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Some remarks about the contact of hypersurfaces along multiple subvarieties

Mauro Beltrametti — 1973

Atti della Accademia Nazionale dei Lincei. Classe di Scienze Fisiche, Matematiche e Naturali. Rendiconti

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.

Seshadri positive submanifolds of polarized manifolds

Lucian BădescuMauro Beltrametti — 2013

Open Mathematics

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...

Sull'annullamento di certi gruppi di coomologia di una varietà normale

Mauro BeltramettiMarino Palleschi — 1979

Atti della Accademia Nazionale dei Lincei. Classe di Scienze Fisiche, Matematiche e Naturali. Rendiconti

In the first part of this work (sects. 1-3) we consider an irreducible normal variety V 3 of dimension 3 in a complex projective space. Let p a ( V 3 ) and P a ( V 3 ) be the virtual arithmetic genus and the second arithmetic genus of V 3 respectively. We prove that the equality p a ( V 3 ) = V a ( V 3 ) holds if and only if V 3 is Cohen-Macaulay. As previously remarked in [11], we obtain the relation P a ( V 3 ) p a ( V 3 ) for any normal V 3 . We also give an example of V 3 ’s on which the inequality P a ( V 3 ) > p a ( V 3 ) holds. The problems we treat here are strictly close to some arguments...

Effect algebras and ring-like structures

Enrico G. BeltramettiMaciej J. Maczyński — 2003

Discussiones Mathematicae - General Algebra and Applications

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,...

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