Le Matematiche (Dipartimento di Matematica e Informatica, Università degli Studi di Catania)
Not a member yet
1189 research outputs found
Sort by
Degree upper bounds for H-Bases
Full text linkThe main objective of this paper is to present upper bounds for the degree of H-bases of polynomial ideals. For this purpose, we introduce the new concept of reduced H-bases and show that the maximal degree of the elements of any reduced H-basis of an ideal is independent of the choice of the basis. Furthermore, we show that, given an ideal, this maximal degree is invariant after performing any linear change of variables on the ideal. These results allow us to establish explicit degree upper bounds in the case of either a zero-dimensional ideal or an ideal generated by a regular sequence
Calderon\u27s reproducing formulas for the Spherical mean L^2-multiplier operators
Full text linkFirst we study the spherical mean L^2-multiplier operators on [0,+∞[xR^n. Next, we give for these operators Calderon\u27s reproducing formulas and best approximation formulas
The large sum graph related to comultiplication modules
Full text linkLet be a commutative ring and be an -module. We define the large sum graph, denoted by , as a graph with the vertex set of non-large submodules of and two distinct vertices are adjacent if and only if is a non-large submodule of . In this article, we investigate the connection between the graph-theoretic properties of and algebraic properties of when is a comultiplication -module
The formal analogy between the stationary axisymmetric Einstein-Maxwell equations and the equations of electrical heating of conductors
Full text linkTwo problems of the general theory of relativity and a problem in the electrical heating of conductors (the so-called thermistor problem), lead to the same set of partial differential equations. This permits a unified treatment of these different problems. The related boundary value problem is studied using a suitable transformation
Positive solutions of nonlinear fractional three-point boundary-value problem
Full text linkIn this paper, we study the existence of positive solutions to the boundary-value problem with fractional order\begin{eqnarray*} \begin{split}(^{C}_{a}D^{\alpha}y)(t)+q(t)f(y)&=0, \hskip 0.5cm 0\leq a<t<b, \hskip 0.5cm 1<\alpha <2,\\\\&y(a)=0, \hskip 0.5 cm y(b)=\beta y(\eta),\end{split}\end{eqnarray*}where a<\eta<b and . We prove the existence of at least one positivesolution when is either superlinear or sublinear using the well-known Guo\u27s fixed point theorem incones. Moreover, the convexity and concavity of the solutions are investigated with respect to the behavior of the function
A semiprime filter-based identity- summand graph of a lattice
Full text linkLet be a proper filter of a lattice with the leastelement and the greatest element . The filter-basedidentity-summand graph of with respect to , denoted by, is the graph with vertices I^*_{F} (L) = \{x\in L \setminus F: x \vee y \in F \, \, \mbox{for some} \, \, y\in L \setminus F \}, and distinct vertices and areadjacent if and only if . We will make anintensive study of the notions of diameter, grith, chromaticnumber, clique number, independence number, domination numberand planar property of this graph. Moreover, Beck\Gamma_{F} (L)$
Copure and 2-absorbing copure submodules
Full text linkLet be a commutative ring with identity and be an -module. In this paper, we will introduce the concept of 2-absorbing copure submodules of as a generalization of copure submodules and obtain some related results. Also, we investigate some results concerning copure submodules
is radio graceful
No full textFor a simple, connected graph, a vertex labeling is called a \emph{radio labeling of } if it satisfies |f(u)-f(v)|\geq\diam(G)+1-d(u,v) for all distinct vertices . If a bijective radio labeling onto exists, is called a \emph{radio graceful} graph. In this paper, we show is radio graceful
alpha-strong approximate solutions to quasi-variational inequalities
No full textIn this paper, based on the regularization of non necessarily semicontinuous set-valued mapsestablished in [4], we prove existence results of strong approximate solutions to quasivariational inequalities,(QVI), without any continuity condition on its related operator. A condition ensuring the convergenceof a sequence of such solutions to an exact one is also provided. Moreover, we observe that the regularizationof [4] leads to new approximate solutions of a weak type. The latter is not in the scope of this noteas it poses a new open geometrical question on the normal cone to a subset, which we underline by theconclusion section
Existence of solution in weighted Sobolev spaces for a strongly nonlinear degenerate elliptic equations having natural growth terms and L^1 data
Full text linkIn this paper we are interested in the existence of a solution for the nonlineardegenerate elliptic equations Lu(x) + H(x; u;∇u) w_2 = f in the setting of theweighted Sobolev space , where H is a nonlinear term with naturalgrowth with respect to ∇u and f ∈L^1(Ω)