Le Matematiche (Dipartimento di Matematica e Informatica, Università degli Studi di Catania)
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Labeling cacti with a condition at distance two
Get PDF An L(2,1)-labeling of a graph G is a function f from the vertex set V(G) to the set of all nonnegative integers such that | f (x)- f (y)| ≥ 2 if d(x, y) = 1 and | f (x) - f (y)| ≥ 1 if d(x, y) = 2. The L(2,1)-labeling number λ(G) of G is the smallest number k such that G has an L(2,1)-labeling with max{f (v) : v Î V(G)} = k. In this paper we present a graph family which has λ-number Δ+1 or Δ+2
On a mixed boundary value problem involving the p-Laplacian
Get PDFIn this paper we prove the existence of infinitely many solutions for a mixed boundary value problem involving the one dimensional p-Laplacian. A result on the existence of three solutions is also established. The approach is based on multiple critical points theorems
Some subordination theorems associated with a new operator
Get PDFIn this paper we introduce a linear operator and obtain certain differential subordination properties associated with this linear operator. Some relevant consequences of the main results including new variations of earlier known results are also pointed out
Covered by lines and Conic connected varieties
Get PDFp, li { white-space: pre-wrap; } We study some properties of an embedded variety covered by lines and give a numerical criterion ensuring the existence of a singular conic through two of its general points. We show that our criterion is sharp. Conic-connected, covered by lines, , , prime Fano, defective, and dual defective varieties are closely related. We study some relations between the above mentioned classes of objects using basic results by Ein and Zak.We study some properties of an embedded variety covered by lines and give a numerical criterion ensuring the existence of a singular conic through two of its general points. We show that our criterion is sharp. Conic-connected, covered by lines, QEL, LQEL, prime Fano, defective, and dual defective varieties are closely related. We study some relations between the above mentioned classes of objects using basic results by Ein and Zak
A note on monotone solutions for a nonconvex second-order functional differential inclusion
Get PDFThe existence of monotone solutions for a second-order functional differential inclusion with Carath\\u27{e}odory perturbation is obtained in the case when the multifunction that define the inclusion is upper semicontinuous compact valued and contained in the Fr\\u27{e}chet subdifferential of a -convex function of order two
Existence results for an elliptic DirichletI problem
Get PDFThe main purpose of this paper is to present recent existence results for an elliptic eigenvalue Dirichlet problem. Precisely, our method ensures the existence of an exactly determined open interval (possibly unbounded) of positive parameters for which the problem admits infinitely many weak solutions
On certain q-Baskakov-Durrmeyer operators
Get PDFIn this paper we introduce a q−analogue of Baskakaov-beta operators. We establish Voronovskaja-type theorem and obtain local error estimates by these q−operators in uniform norm by using the Ditzian-Totik weighted modulus of smoothness for 0 < q < 1
Kober fractional q-derivative operators
Get PDFIn the present paper, we define right and left sided Kober fractional q-derivative operators and show that these derivative operators are left inverse operators of Kober fractional q-integral operators. We obtain the images of generalized basic hypergeometric function and basic analogue of the H-function under these operators. We also deduce several interesting results involving q-analogues of some classical functions as special cases of our main findings
On the symmetric block design with parameters (430, 78, 14)
Get PDFIn this paper we have proved that a Frobenius group of order 301cannot operate on a symmetric block design with parameters (430,78,14)
Subharmonic solutions of planar Hamiltonian systems via the Poincaré́-Birkhoff theorem
Get PDFWe revisit some recent results obtained in [1] about the existence of subharmonic solutions for a class of (nonautonomous) planar Hamiltonian systems, and we compare them with the existing literature. New applications to undamped second order equations are discussed, as well