Search results for " Geometria"
showing 10 items of 291 documents
A laplace type problem for three lattices with non-convex cell
2016
In this paper we consider three lattices with cells represented in Fig. 1, 3 and 5 and we determine the probability that a random segment of constant length intersects a side of lattice. c ⃝2016 All rights reserved.
A topological look at human trabecular bone tissue
2017
Bone quality is affected by trabecular architecture at microscopic level. Various abnormalities of bone tissue lead to altered strength and to an increased susceptibility to fracture, such as Osteoporosis and Osteoarthritis, two major health burdens of our society. These are two complex musculoskeletal diseases that mainly concern bone tissue. In the last twenty years, there has been a growing interest in finding an appropriate topological model for the micro-architecture of trabecular bone tissue. In particular, we prove that these models involve general topological spaces. The appropriate notion to deal with is that of CW-complex.
1-(v,3,r) designs and the equation x+y+z=0 in finite abelian groups
2009
Let (G, +) be a finite abelian group with more than three elements and let B_3 be the family of all the unordered triples {x,y,z} of distinct elements of G such that x+y+z=0. We show that (G, B_3) is a 1-(v,3,r) design if and only if G is either an elementary abelian 3-group or the direct sum of Z/2Z with an elementary abelian 3-group. We also characterize the groups containing at least an element that does not belong to any triple in B_3
A numerical property of Hilbert functions and lex segment ideals
2017
We introduce the fractal expansions, sequences of integers associated to a number. We show that these sequences characterize the Osequences and encode some information about lex segment ideals. Moreover, we introduce numerical functions called fractal functions, and we use them to solve the open problem of the classification of the Hilbert functions of any bigraded algebra.
On the Betti numbers of three fat points in P1 × P1
2019
In these notes we introduce a numerical function which allows us to describe explicitly (and nonrecursively) the Betti numbers, and hence, the Hilbert function of a set Z of three fat points whose support is an almost complete intersection (ACI) in P1 × P1 . A nonrecursively formula for the Betti numbers and the Hilbert function of these configurations is hard to give even for the corresponding set of five points on a special support in P2 and we did not find any kind of this result in the literature. Moreover, we also give a criterion that allows us to characterize the Hilbert functions of these special set of fat points.
New fourfolds from F-theory
2015
In this paper, we apply Borcea-Voisin's construction and give new examples of fourfolds containing a del Pezzo surface of degree six, which admit an elliptic fibration on a smooth threefold. Some of these fourfolds are Calabi-Yau varieties, which are relevant for the $N=1$ compactification of Type IIB string theory known as $F$-Theory. As a by-product, we provide a new example of a Calabi--Yau threefold with Hodge numbers $h^{1,1}=h^{2,1}=10$.
On the existence of at least a solution for functional integral equations via measure of noncompactness
2017
In this article, we use fixed-point methods and measure of noncompactness theory to focus on the problem of establishing the existence of at least a solution for the following functional integral equation ¶ \[u(t)=g(t,u(t))+\int_{0}^{t}G(t,s,u(s))\,ds,\quad t\in{[0,+\infty[},\] in the space of all bounded and continuous real functions on $\mathbb{R}_{+}$ , under suitable assumptions on $g$ and $G$ . Also, we establish an extension of Darbo’s fixed-point theorem and discuss some consequences.
Estudi del llibre Elementos de Geometría plana y descriptiva y nociones de dibujo con aplicación a las labores de la maestra, de Francisca Ferrer i L…
2017
Elementos de Geometría plana y descriptiva y nociones de dibujo con aplicación a las labores de la maestra és un llibre de text per a les Escoles Normals Femenines; Francisca Ferrer i Lecha és una antiga alumna que posteriorment esdevindrà professora de l'Escola Normal de València. Fem un estudi del text, comparant-lo amb dues obres semblants destinades a homes i dones, respectivament. Analitzem el context de l'educació de l'època i, en particular, de la discriminació per gènere i de les Escoles Normals. Elementos de Geometría plana y descriptiva y nociones de dibujo con aplicación a las labores de la maestra is a textbook for the Women's Normal Schools. Francisca Ferrer i Lecha is a former…
Automorphisms of hyperelliptic GAG-codes
2009
Abstract We determine the n –automorphism group of generalized algebraic-geometry codes associated with rational, elliptic and hyperelliptic function fields. Such group is, up to isomorphism, a subgroup of the automorphism group of the underlying function field.
An improvement of a bound of Green
2012
A p-group G of order pn (p prime, n ≥ 1) satisfies a classic Green's bound log p |M(G)| ≤ ½n(n - 1) on the order of the Schur multiplier M(G) of G. Ellis and Wiegold sharpened this restriction, proving that log p |M(G)| ≤ ½(d - 1)(n + m), where |G′| = pm(m ≥ 1) and d is the minimal number of generators of G. The first author has recently shown that log p |M(G)| ≤ ½(n + m - 2)(n - m - 1) + 1, improving not only Green's bound, but several other inequalities on |M(G)| in literature. Our main results deal with estimations with respect to the bound of Ellis and Wiegold.