956 research outputs found
Some remarks on homogeneous K\"ahler manifolds
In this paper we provide a positive answer to a conjecture due to A. J. Di
Scala, A. Loi, H. Hishi (see [3, Conjecture 1]) claiming that a
simply-connected homogeneous K\"ahler manifold M endowed with an integral
K\"ahler form , admits a holomorphic isometric immersion in the
complex projective space, for a suitable . This result has two
corollaries which extend to homogeneous K\"ahler manifolds the results obtained
by the authors in [8] and in [12] for homogeneous bounded domains.Comment: 8 page
Partially Isometric Immersions and Free Maps
In this paper we investigate the existence of ``partially'' isometric
immersions. These are maps f:M->R^q which, for a given Riemannian manifold M,
are isometries on some sub-bundle H of TM. The concept of free maps, which is
essential in the Nash--Gromov theory of isometric immersions, is replaced here
by that of H-free maps, i.e. maps whose restriction to H is free. We prove,
under suitable conditions on the dimension q of the Euclidean space, that
H-free maps are generic and we provide, for the smallest possible value of q,
explicit expressions for H-free maps in the following three settings:
1-dimensional distributions in R^2, Lagrangian distributions of completely
integrable systems, Hamiltonian distributions of a particular kind of Poisson
Bracket.Comment: 19 pages, 1 figur
K\"ahler immersions of K\"ahler-Ricci solitons into definite or indefinite complex space forms
Let be a K\"ahler-Ricci soliton on a complex manifold . We prove
that if the K\"ahler manifold can be K\"ahler immersed into a definite
or indefinite complex space form of constant holomorphic sectional curvature
, then is Einstein. Moreover, its Einstein constant is a rational
multiple of
Preliminari alla ricomposizione dell’opera omnia di Antonio Simon Mossa: le fonti bibliografiche e l’archivio di famiglia
Il ritrovamento, nel 2007, dell’archivio personale di Antonio Simon Mossa ha aperto la strada a un approccio filologico verso una produzione assai più vasta di quanto generalmente ritenuto. Il confronto in atto tra il materiale restituito dall’archivio e la relativamente scarsa bibliografia finora edita si sta rivelando, a lavori ancora in corso, fondamentale punto di partenza per la ricomposizione di un’opera ampia, eclettica, estremamente frazionata e dispersa in una miriade di fonti, molte delle quali ancora da esplorare
LivDet 2017 Fingerprint Liveness Detection Competition 2017
Fingerprint Presentation Attack Detection (FPAD) deals with distinguishing
images coming from artificial replicas of the fingerprint characteristic, made
up of materials like silicone, gelatine or latex, and images coming from alive
fingerprints. Images are captured by modern scanners, typically relying on
solid-state or optical technologies. Since from 2009, the Fingerprint Liveness
Detection Competition (LivDet) aims to assess the performance of the
state-of-the-art algorithms according to a rigorous experimental protocol and,
at the same time, a simple overview of the basic achievements. The competition
is open to all academics research centers and all companies that work in this
field. The positive, increasing trend of the participants number, which
supports the success of this initiative, is confirmed even this year: 17
algorithms were submitted to the competition, with a larger involvement of
companies and academies. This means that the topic is relevant for both sides,
and points out that a lot of work must be done in terms of fundamental and
applied research.Comment: presented at ICB 201
Balanced metrics on homogeneous vector bundles
Let be a holomorphic vector bundle over a compact Kaehler
manifold and let be its
decomposition into irreducible factors. Suppose that each admits a
-balanced metric in Donaldson-Wang terminology. In this paper we prove
that admits a unique -balanced metric if and only if
for all , where denotes
the rank of and . We apply our result to the case
of homogeneous vector bundles over a rational homogeneous variety
and we show the existence and rigidity of balanced Kaehler embedding from into Grassmannians.Comment: 5 page
Dieci partigiani ossesi nella Resistenza italiana
La ricostruzione delle vicende biografiche dei dieci partigiani originari di Ossi finora identificati, riproponendo implicitamente il tema del rapporto fra vicissitudini individuali ed eventi storici, si inserisce nel più ampio contesto del contributo della ricerca locale e settoriale alla storiografia della Resistenza. In tal senso l’articolo, sintesi introduttiva di una monografia in corso di pubblicazione, si propone come ulteriore tassello nel quadro degli studi tuttora in corso sul contributo dei sardi alla guerra di Liberazione
- …