Στοιχεία Τεύχους

Περιοδικό | Δελτίο της Ελληνικής Μαθηματικής Εταιρίας |
---|---|

Αρ. Τεύχους | 49 |

Περίοδος | 2004 |

Έτος Έκδοσης | 2004 |

Σχολικό Έτος | - |

ISSN | 0072-7466 |

Ιδιοκτήτης | ΕΜΕ |

Γλώσσα | Αγγλική-Γαλλική-Γερμανική |

In this paper we systematically treat discrete Gronwall ? Bellman inequalities of the infinity type

In this paper, we shall establish sufficient conditions for the existence of solutions for functional semilinear integrodifferential inclusions in Banach spaces. By using suitable fixed point theorems we study the case when the multivalued map has convex as well nonconvex values

We deal with the ?spectral theory? in the algebra L(V) of linear endomorphisms of an arbitrary vector space V. In the absence, in, principle, of such fundamental notions as least and characteristic polynomials (?infinite matrices?) we have thus to look directly at the individual elements of L(V)

We give spectral characterizations of rank one elements and the socle of a semiprime Banach algebra. The main tool used is the concept of a ? single ? element. If A is any algebra an element s of A is called ? single ? element, if whenever αsb = 0 for some a,b ε A, at least one of as, sb is zero

This paper deals with the very interesting problem about the influence of piecewise smooth boundary conditions on the distribution of the eigenvalues of the negative Laplacian in . The asymptotic expansion of the trace of the wave operator 2121?()exp()tiννμμ?==?Σ t for small | and |t1i=?, where 1{}ννμ?= are the eigenvalues of the negative Laplacian 221()xκκ=??Δ=??Σ in the (12,)xx? plane, is studied for an annular vibrating membrane Ω in together with its smooth inner boundary and its smooth outer boundary . In the present paper a finite number of Dirichlet, Neumann and Robin boundary conditions on the piecewise smooth components of 2R1?Ω2?Ω(1,,jjmΓ=K ) 1?Ω and on the piecewise smooth components (1,jjmn,) Γ=+K of such that 2?Ω11mjj=?Ω=ΓU and 21njjm=+?Ω=ΓUis considered. The basic problem is to extract information on the geometry of the annular vibrating Ω from complete knowledge of its eigenvalues using the wave equation approach by analyzing the asymptotic expansions of the spectral function ?()tμ for small .

The aim of the present note is to establish two new generalizations of a certain trapezoid type integral inequality by using a fairly elementary analysis

The theory of institutions provides an abstract model theory for computation. We internalize ?possible worlds semantics ? and modal satisfaction to institutions with open formulae (open institutions) and fulfilling certain mild technical conditions. Modalities then, can be defined on ? top ? of any such institution proving that modal extensions are not a privilege of certain logics ? like the first order one ? but can be generated over a much wider variety of institutions

We consider the electromagnetic scattering of time ? harmonic spherical waves by a spheroidal perfect conductor imbedded in a semi ? infinite dielectric medium. After settling an integral equation formulation of the problem we establish a theoretical model describing analytically the underlying scattering process. The proposed analysis results in the determination of the scattered field in the observation environment along with its multivariable dependence on several physical and geometric parameters of the system.