7 results
Search Results
2. Sull'esistenza di certe configurazioni geometriche collegate ai piani proiettivi di ordine 10
- Author
-
Giorgio Faina
- Subjects
Discrete mathematics ,Steiner system ,General Mathematics ,Turn (geometry) ,Order (group theory) ,Algebra over a field ,Arithmetic ,Mathematics - Abstract
In this paper it is shown that there is no abstract oval of order 10. Also it is shown that there is no partial geometrypg (6,9,4), which in turn would imply the nonexistence of Steiner systemS(3,12,112).
- Published
- 1984
3. Coni generalizzati e piani di Laguerre
- Author
-
Giorgio Faina
- Subjects
Combinatorics ,Cone (topology) ,General Mathematics ,Laguerre polynomials ,Family of sets ,Algebra over a field ,piani di Laguerre ,Automorphism ,Finite set ,Mathematics ,Incidence (geometry) - Abstract
LetE be an abstract infinite or finite set with |E|≥3 and letB be a non empty family of subsets ofE such that there exists at least a partitionF ofE withF⊆B. We callgeneralized cone some incidence structures (E,B,F) which comprehend ovoidal and Miquelian Laguerre planes, special Laguerre planes, Parabeln-Ebene and other interesting incidence structures. In this paper we investigate suchgeneralized cones and their automorphism groups and give some characterizations of ovoidal (Miquelian) Laguerre planes.
- Published
- 1994
4. Considerazioni di Giovanni Rizzetti sul calcolo delle probabilità e sul teorema di Jakob Bernoulli
- Author
-
G. Fenaroli, A.C. Garibaldi, and A. Belcastro
- Subjects
History ,Mathematics(all) ,Group (mathematics) ,General Mathematics ,limit theorems ,Argumentation theory ,Bernoulli's principle ,Law of large numbers ,Bernoulli's theorem ,Calculus ,stochastic processes ,history of probability ,Humanities ,Mathematics - Abstract
This paper focuses on the writings on probability by Giovanni Rizzetti (1675–1751), who was a member of the group of Venetian scholars around Count Jacopo Riccati (1676–1754). We deal with his approach to probability and, more particularly, with his argumentation on Bernoulli's theorem. The research develops Rizzetti's reasonings as contained in his printed works (1724–1729) as well as in certain key manuscripts. The texts of the latter may be found in the appendix. The statements of Rizzetti seem very interesting; they are situated between the empirical law of chance and the law of large numbers.
- Published
- 1994
5. Trasformate di Radon e operatori di convoluzione su gruppi e algebre di Lie
- Author
-
Giancarlo Travaglini and Travaglini, G
- Subjects
Pure mathematics ,General Mathematics ,Real form ,operatori di convoluzione ,Killing form ,Affine Lie algebra ,Lie conformal algebra ,Graded Lie algebra ,Algebra ,Adjoint representation of a Lie algebra ,Representation of a Lie group ,Lie algebra ,MAT/05 - ANALISI MATEMATICA ,Mathematics - Abstract
The following is an expository paper concerning the relations between Radon transforms and convolution operators associated to singular measures. A quick review of the classical theorems is presented and a recent result of F. Ricci and the author in the framework of compact Lie groups and Lie algebras is outlined. © 1995 Birkhäuser-Verlag.
- Published
- 1995
6. Combinatorics and topology of toric arrangements defined by root systems
- Author
-
Luca Moci and Moci, Luca
- Subjects
Connected component ,Polynomial ,General Mathematics ,Torus ,Combinatorics ,symbols.namesake ,Dynkin diagram ,Euler characteristic ,symbols ,FOS: Mathematics ,Algebraic Topology (math.AT) ,Mathematics - Combinatorics ,Affine transformation ,Combinatorics (math.CO) ,Mathematics - Algebraic Topology ,14N10, 17B10, 20G20 ,Representation Theory (math.RT) ,Partially ordered set ,Mathematics - Representation Theory ,Mathematics ,Complement (set theory) - Abstract
Given the toric (or toral) arrangement defined by a root system $\Phi$, we describe the poset of its layers (connected components of intersections) and we count its elements. Indeed we show how to reduce to zero-dimensional layers, and in this case we provide an explicit formula involving the maximal subdiagrams of the affine Dynkin diagram of $\Phi$. Then we compute the Euler characteristic and the Poincare' polynomial of the complement of the arrangement, which is the set of regular points of the torus., Comment: 20 pages. Updated version of a paper published in December 2008
- Published
- 2008
7. On the X-rank with respect to linear projections of projective varieties
- Author
-
Alessandra Bernardi, Edoardo Ballico, University of Trento [Trento], Geometry, algebra, algorithms (GALAAD), Inria Sophia Antipolis - Méditerranée (CRISAM), Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Université Nice Sophia Antipolis (1965 - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Centre National de la Recherche Scientifique (CNRS), European Project: 252367,EC:FP7:PEOPLE,FP7-PEOPLE-2009-IEF,DECONSTRUCT(2010), Edoardo Ballico, Alessandra Bernardi, and Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Université Nice Sophia Antipolis (... - 2019) (UNS)
- Subjects
Linearly normal curve ,MAT/03 Geometria ,General Mathematics ,[MATH.MATH-AC]Mathematics [math]/Commutative Algebra [math.AC] ,010103 numerical & computational mathematics ,Rank (differential topology) ,Rational normal curve ,Commutative Algebra (math.AC) ,01 natural sciences ,Projection (linear algebra) ,Combinatorics ,Mathematics - Algebraic Geometry ,FOS: Mathematics ,0101 mathematics ,Algebraic Geometry (math.AG) ,Projective variety ,Mathematics ,Rank ,Secant Varieties ,Rational Normal Curves ,Projections ,010102 general mathematics ,Mathematics - Commutative Algebra ,Linear subspace ,SYMMETRIC TENSORS ,rank ,14N05, 14H50 ,Tangential varietie ,SECANT VARIETIES ,[MATH.MATH-AG]Mathematics [math]/Algebraic Geometry [math.AG] ,Element (category theory) ,Subspace topology ,Osculating circle - Abstract
In this paper we improve the known bound for the $X$-rank $R_{X}(P)$ of an element $P\in {\mathbb{P}}^N$ in the case in which $X\subset {\mathbb P}^n$ is a projective variety obtained as a linear projection from a general $v$-dimensional subspace $V\subset {\mathbb P}^{n+v}$. Then, if $X\subset {\mathbb P}^n$ is a curve obtained from a projection of a rational normal curve $C\subset {\mathbb P}^{n+1}$ from a point $O\subset {\mathbb P}^{n+1}$, we are able to describe the precise value of the $X$-rank for those points $P\in {\mathbb P}^n$ such that $R_{X}(P)\leq R_{C}(O)-1$ and to improve the general result. Moreover we give a stratification, via the $X$-rank, of the osculating spaces to projective cuspidal projective curves $X$. Finally we give a description and a new bound of the $X$-rank of subspaces both in the general case and with respect to integral non-degenerate projective curves., 10 pages
- Published
- 2009
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.