Advanced search    

Search: authors:"Donal O'Regan"

33 papers found.
Use AND, OR, NOT, +word, -word, "long phrase", (parentheses) to fine-tune your search.

Volterra and Urysohn integral equations in Banach spaces

Journal of Applied Mathematics and Stochastic Analysis VOLTERRA AND URYSOHN INTEGRAL EQUATIONS IN BANACH SPACES 0 DONAL O'REGAN University College Galway, Department We use topological methods to

Volterra and Urysohn integral equations in Banach spaces

Journal of Applied Mathematics and Stochastic Analysis VOLTERRA AND URYSOHN INTEGRAL EQUATIONS IN BANACH SPACES 0 DONAL O'REGAN University College Galway, Department We use topological methods to

An upper and lower solution approach for a generalized Thomas–Fermi theory of neutral atoms

This paper presents an upper and lower solution theory for boundary value problems modelled from the Thomas–Fermi equation subject to a boundary condition corresponding to the neutral atom with Bohr radius.

Essential ?cκ-type maps and Birkhoff-Kellogg theorems

Hindawi Publishing Corporation Journal of Applied Mathematics and Stochastic Analysis 0 Donal O'Regan: Department of Mathematics, National University of Ireland , Galway , Ireland E-mail address

An upper and lower solution approach for a generalized Thomas–Fermi theory of neutral atoms

This paper presents an upper and lower solution theory for boundary value problems modelled from the Thomas–Fermi equation subject to a boundary condition corresponding to the neutral atom with Bohr radius.

Fixed point theory for Mönch-type maps defined on closed subsets of Fréchet spaces: the projective limit approach

Hindawi Publishing Corporation International Journal of Mathematics and Mathematical Sciences RAVI P. AGARWAL JEWGENI H. DSHALALOW DONAL O'REGAN New Leray-Schauder alternatives are presented for Mo ... : Department of Mathematical Sciences, College of Science, Florida Institute of Technology, Melbourne, FL 32901 -6975, USA E-mail address: Donal O'Regan : Department of Mathematics, National University of

A singular initial value problem for some functional differential equations

Hindawi Publishing Corporation Journal of Applied Mathematics and Stochastic Analysis RAVI P. AGARWAL 0 DONAL O'REGAN 0 OLEKSANDR E. ZERNOV 0 0 Donal O'Regan: Department of Mathematics, National

Geodesic B-Preinvex Functions and Multiobjective Optimization Problems on Riemannian Manifolds

We introduce a class of functions called geodesic -preinvex and geodesic -invex functions on Riemannian manifolds and generalize the notions to the so-called geodesic quasi/pseudo -preinvex and geodesic quasi/pseudo -invex functions. We discuss the links among these functions under appropriate conditions and obtain results concerning extremum points of a nonsmooth geodesic...

Krasnosel’skii Type Fixed Point Theorems for Mappings on Nonconvex Sets

We prove Krasnosel'skii type fixed point theorems in situations where the domain is not necessarily convex. As an application, the existence of solutions for perturbed integral equation is considered in p-normed spaces.

Degenerate Anisotropic Differential Operators and Applications

The boundary value problems for degenerate anisotropic differential operator equations with variable coefficients are studied. Several conditions for the separability and Fredholmness in Banach-valued spaces are given. Sharp estimates for resolvent, discreetness of spectrum, and completeness of root elements of the corresponding differential operators are obtained. In the last...

Existence results of Brezis-Browder type for systems of Fredholm integral equations

In this article, we consider the following systems of Fredholm integral equations: u i ( t ) = h i ( t ) + ∫ 0 T g i ( t , s ) f i ( s , u 1 ( s ) , u 2 ( s ) , … , u n ( s ) ) d s , t ∈ [ 0 , T ] , 1 ≤ i ≤ n , u i ( t ) = h i ( t ) + ∫ 0 ∞ g i ( t , s ) f i ( s , u 1 ( s ) , u 2 ( s ) , … , u n ( s ) ) d s , t ∈ [ 0 , ∞ ) , 1 ≤ i ≤ n . Open image in new window Using an argument...

Existence results of Brezis-Browder type for systems of Fredholm integral equations

In this article, we consider the following systems of Fredholm integral equations: u i ( t ) = h i ( t ) + ∫ 0 T g i ( t , s ) f i ( s , u 1 ( s ) , u 2 ( s ) , … , u n ( s ) ) d s , t ∈ [ 0 , T ] , 1 ≤ i ≤ n , u i ( t ) = h i ( t ) + ∫ 0 ∞ g i ( t , s ) f i ( s , u 1 ( s ) , u 2 ( s ) , … , u n ( s ) ) d s , t ∈ [ 0 , ∞ ) , 1 ≤ i ≤ n . Using an argument originating from Brezis...

Positive Solutions of Singular Complementary Lidstone Boundary Value Problems

We investigate the existence of positive solutions of singular problem , , , . Here, and the Carathéodory function may be singular in all its space variables . The results are proved by regularization and sequential techniques. In limit processes, the Vitali convergence theorem is used.

Fixed Point Theorems for ws-Compact Mappings in Banach Spaces

We present new fixed point theorems for ws-compact operators. Our fixed point results are obtained under Sadovskii, Leray-Schauder, Rothe, Altman, Petryshyn, and Furi-Pera type conditions. An example is given to show the usefulness and the applicability of our results.

Multiplicity Results Using Bifurcation Techniques for a Class of Fourth-Order -Point Boundary Value Problems

By using bifurcation techniques, this paper investigates the existence of nodal solutions for a class of fourth-order -point boundary value problems. Our results improve those in the literature.

Browder-Krasnoselskii-Type Fixed Point Theorems in Banach Spaces

We present some fixed point theorems for the sum of a weakly-strongly continuous map and a nonexpansive map on a Banach space . Our results cover several earlier works by Edmunds, Reinermann, Singh, and others.

Fixed Point Theory for Admissible Type Maps with Applications

We present new Leray-Schauder alternatives, Krasnoselskii and Lefschetz fixed point theory for multivalued maps between Fréchet spaces. As an application we show that our results are directly applicable to establish the existence of integral equations over infinite intervals.

An Approximation Approach to Eigenvalue Intervals for Singular Boundary Value Problems with Sign Changing and Superlinear Nonlinearities

This paper studies the eigenvalue interval for the singular boundary value problem , where may be singular at ,  , and may change sign and be superlinear at . The approach is based on an approximation method together with the theory of upper and lower solutions.