Existence of critical points in a general setting

The paper proves the existence of critical points for a general locally Lipschitz functional usually arising in nonlinear elliptic problems. It extends and unifies various results in the critical point theory. The applications treat new situations involving discontinuous elliptic equations containing both sublinear and superlinear terms, integro-differential equations and nonlinear elliptic systems.     

Multiple solutions of Schrödinger equations with indefinite linear part and super or asymptotically linear terms

Based on new information concerning strongly indefinite functionals without Palais-Smale conditions, we study existence and multiplicity of solutions of the Schrödinger equation

     

Bifurcating critical points of bending energy under constraints related to the shape of red blood cells

Considered is a variational problem for the bending energy of closed surfaces under the prescribed area and surrounding volume. Minimizers of this problem are interpreted as surfaces modeling the shape of red blood cells. We give a rigorous proof of the existence of a one-parameter family of critical points bifurcating from the sphere and study their stability/instability. In particular, for a few branches of critical points, we compute the exact values of the index and the nullity of critical points. Received: 8 September 2001 / Accepted: 25 October 2001 / Published online: 29 April 2002 Partly supported by Grant-in-Aid for Exploratory Research (Nos.09874026, 11874033) and for Scientific Research (No.12640200), Ministry of Education, Science, Sports, and Culture, Japan; and also by Sumitomo Foundation Dedicated to Professor Takaaki Nishida on his sixtieth birthday     

Erratum to “Time harmonic wave diffraction problems in materials with sign-shifting coefficients” [J. Comput. Appl. Math. doi:10.1016/j.cam.2009.08.041]

We mention here an error in the statement of the configurations that are covered by the theory of T-coercivity presented in the paper “Time harmonic wave diffraction problems in materials with sign-shifting coefficients” [J. Comput. Appl. Math. doi:10.1016/j.cam.2009.08.041].     

Self‐adjointness of perturbed biharmonic operators on Riemannian manifolds

We give a sufficient condition for the essential self‐adjointness of a perturbed biharmonic‐type operator acting on sections of a Hermitian vector bundle on a geodesically complete Riemannian manifold with Ricci curvature bounded from below by a (possibly unbounded) non‐positive function depending on the distance from a reference point. We also establish the separation property in the case when the corresponding operator acts on functions.     

Erratum to “State-morphism MV-algebras” [Ann. Pure Appl. Logic 161 (2009) 161-173]

Recently, the first two authors characterized in Di Nola and Dvure?enskij (2009) [1] subdirectly irreducible state-morphism MV-algebras. Unfortunately, the main theorem (Theorem 5.4(ii)) has a gap in the proof of Claim 10, as the example below shows. We now present a correct characterization and its correct proof.     

The concentration behavior of ground state solutions for a critical fractional Schrödinger–Poisson system

In this paper, we study the following critical fractional Schrödinger–Poisson system where is a small parameter, and , is the fractional critical exponent for 3‐dimension, has a positive global minimum, and are positive and have global maximums. We obtain the existence of a positive ground state solution by using variational methods, and we determine a concrete set related to the potentials and Q as the concentration position of these ground state solutions as . Moreover, we consider some properties of these ground state solutions, such as convergence and decay estimate.     

Remark on: “Exp-function method for the exact solutions of fifth order KdV equation and modified Burgers equation” [Appl. Math. Comput. (2009) doi:10.1016/j.amc.2009.07.009]

By means of the Exp-function method, Inan and Ugurlu [Appl. Math. Comput. (2009) doi:10.1016/j.amc.2009.07.009] reported eight expressions for being solutions to the two equations studied. In fact, all of them can be easily simplified to constants.     

Correction to: “Algebraic topology of Peano continua” [Topology Appl. 153 (2-3) (2005) 213-226] and “Fundamental groups having the whole information of spaces” [Topology Appl. 146-147 (2005) 317-328]

We correct lemmata in the papers in the title.     

A resolvent approach to the stability of essential and critical spectra of perturbed <Emphasis Type="Italic">C</Emphasis><Subscript>0</Subscript>-semigroups on Hilbert spaces with applications to transport theory

We give sufficient conditions in terms of resolvents implying the stability of the essential or critical spectra of perturbed C₀-semigroups on Hilbert spaces. We also show how these results apply to transport theory.     

Addendum to “Distribution of points on the circle” [J. Number Theory 127 (1) (2007) 127-135]

In an earlier paper we gave a result relating the value of an exponential sum with the distribution of summands in the arcs of the unit circle in the complex plane. In a marginal case, this result is superseded by a result of Lev. In this addendum we use an idea of Lev to give a new proof of our earlier result and to improve upon the marginal result.     

A variational approach to the local character of G-closure: the convex case

This article is devoted to characterize all possible effective behaviors of composite materials by means of periodic homogenization. This is known as a G-closure problem. Under convexity and p  -growth conditions (p>1$p>1$), it is proved that all such possible effective energy densities obtained by a Γ-convergence analysis, can be locally recovered by the pointwise limit of a sequence of periodic homogenized energy densities with prescribed volume fractions. A weaker locality result is also provided without any kind of convexity assumption and the zero level set of effective energy densities is characterized in terms of Young measures. A similar result is given for cell integrands which enables to propose new counter-examples to the validity of the cell formula in the nonconvex case and to the continuity of the determinant with respect to the two-scale convergence.