DSpace Collection:http://www.openstarts.units.it:80/dspace/handle/10077/41272016-05-24T15:44:09Z2016-05-24T15:44:09ZOn some Semilinear Periodic Parabolic ProblemsGodoy, TomasKaufmann, Urielhttp://www.openstarts.units.it:80/dspace/handle/10077/41382011-05-03T07:35:01Z2006-01-01T00:00:00ZTitle: On some Semilinear Periodic Parabolic Problems
Authors: Godoy, Tomas; Kaufmann, Uriel
Abstract: Let $\Omega \subset \mathbb R^N$ a smooth bounded domain. We study
existence and nonexistence of positive solutions for some semilinear
Dirichlet periodic parabolic problems of the form
$Lu = h(x,t,u)$ in $\Omega\times \mathbb R$
for a class of Caratheodory functions
$h : \Omega\times \mathbb R \times [0,\infty) \rightarrow \mathbbR$
such that h (., 0) = 0 and $\lim_{\xi\rightarrow 0^+}\xi^{ −1}h (.,\xi) = 0$
or $-\infty$. All results remain true for the corresponding elliptic
problems.
Type: Articolo2006-01-01T00:00:00ZA Note on Gevrey Well-Posedness for the Operator $\partial^2_t - a(t)\partial _x(b(t,x)\partial_x)$Del Santo, Danielehttp://www.openstarts.units.it:80/dspace/handle/10077/41372011-03-16T00:35:14Z2006-01-01T00:00:00ZTitle: A Note on Gevrey Well-Posedness for the Operator $\partial^2_t - a(t)\partial _x(b(t,x)\partial_x)$
Authors: Del Santo, Daniele
Abstract: We use a Littlewood-Paley decomposition to obtain a
Gevrey-well-posedness result for a weakly hyperbolic equation in
one space variable with coefficients depending also on x.
Type: Articolo2006-01-01T00:00:00ZAlgebraic Aspects of Commutation of Linear Operators up to a FactorBellonotto, B.Teppati, Giancarlohttp://www.openstarts.units.it:80/dspace/handle/10077/41362011-03-16T00:35:13Z2006-01-01T00:00:00ZTitle: Algebraic Aspects of Commutation of Linear Operators up to a Factor
Authors: Bellonotto, B.; Teppati, Giancarlo
Abstract: When representing projective geometry by means of a
vector space, commutativity can be replaced by commutativity up
to a factor. This feature was investigated by F. Cecioni under
very weak assumptions, but it is hard to generalize the methods
of [4] to a wider algebraic context. In this note, we develop the
independent treatment of H. Weyl, and extend the approach of to non-commutative rings under suitable assumptions on the
endomorphisms. From this point of view, we show that commutativity of operators up to a non-trivial factor is an exceptional
phenomenon in comparison to strict commutativity.
Type: Articolo2006-01-01T00:00:00ZHyperbolic Knots and Links with a Common Cyclic Branched Covering: Known Results and Open ProblemsZimmermann, Bruno P.http://www.openstarts.units.it:80/dspace/handle/10077/41352011-03-16T00:35:12Z2006-01-01T00:00:00ZTitle: Hyperbolic Knots and Links with a Common Cyclic Branched Covering: Known Results and Open Problems
Authors: Zimmermann, Bruno P.
Abstract: We give a survey on recent progress and remaining
open problems on the number and the geometry of knots and
links which have a hyperbolic 3-manifold M as a common cyclic
branched covering. This is strongly related to the algebra and
the geometry of the finite isometry group G of M, and it naturally divides into the two cases G solvable and G non-solvable.
The solvable case is relatively well understood whereas the non-
solvable case remains somewhat mysterious.
Type: Articolo2006-01-01T00:00:00Z