Search results for "Geometria"
showing 10 items of 422 documents
Regularity of isoperimetric profiles
2008
In this short paper we summerize some results about the analyticity of isoperimetric profiles recently appeared in the specialized literature.
A spinorial decomposition of gl_4(R)
2010
We determine six invariant subspaces of the 16-dimensional space gl_4(R) under the conjugation by any element in Spin_3(R). Four of them add up to the 10-dimensional space of symmetric matrices and the other two add up to the 6-dimensional space of skew-symmetric matrices.
Steiner systems and configurations of points
2020
AbstractThe aim of this paper is to make a connection between design theory and algebraic geometry/commutative algebra. In particular, given any Steiner SystemS(t, n, v) we associate two ideals, in a suitable polynomial ring, defining a Steiner configuration of points and its Complement. We focus on the latter, studying its homological invariants, such as Hilbert Function and Betti numbers. We also study symbolic and regular powers associated to the ideal defining a Complement of a Steiner configuration of points, finding its Waldschmidt constant, regularity, bounds on its resurgence and asymptotic resurgence. We also compute the parameters of linear codes associated to any Steiner configur…
Standard classes on the blow-up of $\mathbb{P}^n$ at points in very general position
2012
A conjecture on special linear systems of $mathbb{P}^3$
2005
Lectures on Lipschitz analysis
2005
NEAR-RINGS AND GROUPS OF AFFINE MAPPINGS
2013
We classify semi-topological locally compact and semi-algebraic near-rings R where the set of non-invertible elements of R forms an ideal I of R such that the multiplicative group of R/I acts sharply transitively on I\{0}. To achieve our results we use as a main tool the classi cation of locally compact and algebraic (2; 2)-transformation groups given in two previuos papers.
Luigi Cremona's Years in Bologna: From Research to Social Commitment
2012
Luigi Cremona (1830-1903), unanimously considered to be the man who laid the foundations of the prestigious Italian school of Algebraic Geometry, was active at the University of Bologna from October 1860,when assigned by the Minister Terenzio Mamiani (1799-1885) to cover the Chair of Higher Geometry, until September 1867 when Francesco Brioschi (1824-1897) called it to the Politecnico di Milano. The "Bolognese years" were Cremona's richest and most significant in terms of scientific production,and, at the same time, were the years when he puts the basis for its most important interventions in the social and political life of the "newborn" kingdom of Italy. In this article we present these d…
On the variations of the Betti numbers of regular levels of Morse flows
2011
Abstract We generalize results in Cruz and de Rezende (1999) [7] by completely describing how the Betti numbers of the boundary of an orientable manifold vary after attaching a handle, when the homology coefficients are in Z, Q, R or Z p Z with p prime. First we apply this result to the Conley index theory of Lyapunov graphs. Next we consider the Ogasa invariant associated with handle decompositions of manifolds. We make use of the above results in order to obtain upper bounds for the Ogasa invariant of product manifolds.
I matematici italiani e i "misteri riemanniani". La geometria italiana della prima metà del XX secolo tra intuizione e rigore
2009
La permanenza di Riemann a Pisa, i suoi rapporti diretti con Enrico Betti e, indiretti, con Beltrami, Casorati e Cremona portarono mutamenti profondi in tutti i campi della matematica (e della filosofia della matematica) italiane. Nel mio intervento focalizzerò l’attenzione su alcuni punti, soprattutto riguardo la geometria algebrica italiana e i suoi rapporti con l’analisi complessa nei primi trenta anni del XX secolo, nonché il formarsi di un modo “italiano” di guardare alla geometria. Un esame accurato dello sviluppo storico della geometria italiana non può prescindere dall’esame degli apporti determinanti dati dalle scuole tedesca e francese allo sviluppo dell’interpretazione geometrica…