Rendiconti dell’Istituto di Matematica dell’Università di Trieste: an International Journal of Mathematics vol.56 (2024)

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https://www.openstarts.units.it/handle/10077/36459

Contents

Eglantina Kalluçi, Bujar Xh. Fejzullahu
New inequalities for the confluent hypergeometric function

Gianni Bosi, Roberto Daris, Gabriele Sbaiz
New characterizations of completely useful topologies in mathematical utility theory

Horst Alzer, Mehdi Hassani
Inequalities for the arithmetic mean of the first n prime numbers

Prasenjit Bal, Susmita Sarkar
Characterizations of strongly star-Rothberger spaces by means of sequential singletonic intersection property and selection principles

Ina Hajdini, Orlin Stoytchev
The fundamental group of SO(n) via quotients of braid groups

Benedetto Silvestri
Construction of strong derivable maps via functional calculus of unbounded spectral operators in Banach spaces

Hassina Grar, Zahira Kebaili
A new version of projection method for variational inequalities problem with nonlinear constraints

Adriano Peixoto
Existence of positive solution for a nonlinear problem with mixed conditions

Raquel Mallavibarrena, Ragni Piene
On fundamental forms and osculating bundles

Alessandro Calamai, Matteo Franca, Michal Pospíšil
On the dynamics of non-autonomous systems in a neighborhood of a homoclinic trajectory

Parthiba Das, Prasenjit Bal
Statistical Convergence Restricted by Weight Functions and its Application in the Variation of γ-covers

Ahmed Rikouane, Mohamed Laghdir
Duality for a properly efficient solution of bilevel multiobjective fractional programming problems with extremal-value function

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Now showing 1 - 5 of 13

Duality for a properly efficient solution of bilevel multiobjective fractional programming problems with extremal-value function
(2024)
Rikouane, Ahmed
;
Laghdir, Mohamed
In this paper, we establish some results regarding the optimality conditions and duality properties for properly efficient solutions of a constrained bilevel multiobjective fractional programming problem (P) with an extremal-value function. These results are obtained by applying a parametric approach to reduce the problem (P) to a parametric problem (P^μ) with μ ∈ R^p, and we obtain optimality conditions for properly efficient solutions for these problems. Furthermore, we define a dual problem of (P^μ) and we establish some results on duality.
67 36
Statistical Convergence Restricted by Weight Functions and its Application in the Variation of γ-covers
(2024)
Das, Parthiba
;
Bal, Prasenjit
In this paper, we utilize a weight function g to regulate the pace of the statistical convergence in a topological space. We extend the notion of statistical convergence to weighted statistical convergence by utilizing the weighted density. Using this intriguing idea of convergence, a new variation of γ-covers (referred to as s_g-γ cover) is introduced. Subsequently some topological analysis are conducted on the class of s_g-γ coverings. It is demonstrated that the new class of s_g-γ coverings lies some where between the class of γ-covers and the class of s-γ cover classes.
37 29
On the dynamics of non-autonomous systems in a neighborhood of a homoclinic trajectory
(2024)
Calamai, Alessandro
;
Franca, Matteo
;
Pospíšil, Michal
This article is devoted to the study of a 2-dimensional piecewise smooth (but possibly) discontinuous dynamical system, subject to a non-autonomous perturbation; we assume that the unperturbed system admits a homoclinic trajectory ⃗γ(t). Our aim is to analyze the dynamics in a neighborhood of ⃗γ(t) as the perturbation is turned on, by defining a Poincar´e map and evaluating fly time and space displacement of trajectories performing a loop close to ⃗γ(t). Besides their intrinsic mathematical interest, these results can be thought of as a first step in the analysis of several interesting problems, such as the stability of a homoclinic trajectory of a non-autonomous ODE and a possible extension of Melnikov chaos to a discontinuous setting.
58 36
On fundamental forms and osculating bundles
(2024)
Mallavibarrena, Raquel
;
Piene, Ragni
We define higher order fundamental forms and osculating spaces of projective algebraic varieties, using sheaves of principal parts. We show that the mth fundamental form can be viewed as the differential of the (m−1)th Gauss map, and explain why the vanishing of the mth fundamental form implies that the variety is contained in a general (m − 1)th osculating space. Pointwise, the fundamental forms give linear systems on the projectivized tangent spaces. We show that, at each point, the Jacobian of the mth fundamental form is contained in the (m − 1)th fundamental form. In the case of ruled varieties, we describe these linear systems. We discuss conditions for a surface to be ruled, in terms of the second fundamental form and the Fubini cubic.
63 42
Existence of positive solution for a nonlinear problem with mixed conditions
(2024)
Peixoto, Adriano
In this work, we prove the existence of a positive solution to the second-order nonlinear problem u′′ + f(t, u, u′) = 0 with mixed boundary conditions, where f is an Lp-Carath´eodory function satisfying certain properties. Three boundary conditions are analysed. Furthermore, we also prove the existence of a positive solution to the problem u′′ + b(t)g(u) = 0, where b(t) is an L1 function and g(u) is a continuous function. The proofs of the results are based on the Mawhin’s coincidence degree.
23 23

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