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Articles 2581 - 2595 of 2595

Full-Text Articles in Physical Sciences and Mathematics

Pirinciples Of Radiation For Helmholtz Equation In N-Dimensional Layer With Impedence Boundary Conditions., B. A. Iskenderov, A. I. Mehtieva Jan 1996

Pirinciples Of Radiation For Helmholtz Equation In N-Dimensional Layer With Impedence Boundary Conditions., B. A. Iskenderov, A. I. Mehtieva

Turkish Journal of Mathematics

The principle of limit absorption and A. G. Sveshnikov's partial conditions of radition for Helmholts equation in multile dimensinal layer with impedance boundary conditions were studied. The behavior of the solutions of corresponding initial-boundary value problem for non-stationary wave equations as t \ra+\infty was studied too.


On Affine Selection And Separation Of Vector Valued Functions, S. Alpay, Z. Ercan Jan 1996

On Affine Selection And Separation Of Vector Valued Functions, S. Alpay, Z. Ercan

Turkish Journal of Mathematics

Let K be a Choquet simplex, E a Fr\'{e}chet space and \Phi: K \ra 2^E a map such that \Phi(x) is closed and convex for each x \in K. A sufficient condition is given for \Phi to have a continuous affine selection.This is employed to prove a separation theorem for vector valued semicontinuous functions from a Choquet simplex into an ordered Fr\'{e}chet space.


Fixed Points And Completeness, Z. Liu Jan 1996

Fixed Points And Completeness, Z. Liu

Turkish Journal of Mathematics

We give five necessary and sufficient conditions for a metric space to be complete.


On Spaces Of Generalized Dirichlet Series, M. Dragilev Jan 1996

On Spaces Of Generalized Dirichlet Series, M. Dragilev

Turkish Journal of Mathematics

It is considered the relationship between spaces L_f(\lambda,\sigma) and subspaces of the space A_1(\bar{A}_1) of analytic functions in the open (closed) unit disc, generated by systems F(\alpha_nz), n\in N, if they constitute a basis in their closure.


Zeros Of Derivatives Of Dirichlet L-Functions, C. Yalçin Yildirim Jan 1996

Zeros Of Derivatives Of Dirichlet L-Functions, C. Yalçin Yildirim

Turkish Journal of Mathematics

In this paper diverse results on the location and number of zeros of derivatives of Dirichlet L-functions are proved.


A Note On Gamma Rings, M. Sapanci, A. Nakajimaz Jan 1996

A Note On Gamma Rings, M. Sapanci, A. Nakajimaz

Turkish Journal of Mathematics

Let M be a \Gamma-ring and D a non-zero left derivation on M. We show that if there exists an element m in M such that D(m) is a right non-zero divisor, then M is commutative.


On A Differential Analog Of The Prime-Radical And Properties Of The Lattice Of Radical Differential Ideals In Associative Differential Rings, D. Hadjiev, F. Çallialp, A. Eden Jan 1996

On A Differential Analog Of The Prime-Radical And Properties Of The Lattice Of Radical Differential Ideals In Associative Differential Rings, D. Hadjiev, F. Çallialp, A. Eden

Turkish Journal of Mathematics

In this paper we prove the following results: (1) For any assosiative differential ring with the unit we introduce a differential analog of the prime-radical and describe it; (2) any maximal differential ideal of a Ritt algebra is prime; (3) The lattice of radical differential ideals satisfies the condition of infinite \cap- distributivity.


Finite Dimensional Attractors For A Class Of Semilinear Wave Equations, A. Eden, V. Kalantarov Jan 1996

Finite Dimensional Attractors For A Class Of Semilinear Wave Equations, A. Eden, V. Kalantarov

Turkish Journal of Mathematics

In this paper we give a self-contained survey of results related with the global attractors for a class of nonlinear wave equations with damping or viscosity terms. In particular, we prove the existence of a finite dimensional attractor and estimate its fractal dimension by imbedding it in an exponential attractor. Some results on global stability, existence of finite dimensional attractors were already partially discussed in Kalantarov [44] and in Eden et. al. [25], however we simplify the framework by introducing a unified approach to both the existence of attractors through \alpha-contractions and the construction of exponential attractors via some Lipschitzianity …


Comparison Of Invariants For Triples Of Hilbert Spaces, P. A. Chalov Jan 1996

Comparison Of Invariants For Triples Of Hilbert Spaces, P. A. Chalov

Turkish Journal of Mathematics

In [2,3] the sequence of invariant characteristics (\mu_{m}) for the finite families of Hilbert spaces were considered. Here we make a comparison of these invariants among themselves. We construct some examples of triples of Hilbert spaces, which show that each system of the first r+1 characteristics is stronger than the system of the first r of them. Moreover we show that there exist triples of Hilbert spaces which on the one hand are not quasidiagonally isomorphic, but on the other hand they cannot be distinguished by any function \mu_{m},\,\, m\in\,\, \Bbb N.


An Extension Of The Binomial Theorem With Application To Stability Theory, Z. Zahreddinea Jan 1996

An Extension Of The Binomial Theorem With Application To Stability Theory, Z. Zahreddinea

Turkish Journal of Mathematics

We show how it is possible to put different stability types such as Routh-Hurwitz and Schur-Cohn on common grounds by establishing direct links between them. In the process, we obtain natural and elegant extensions of both Pascal's rule and the binomial theorem, which prove useful in establishing our main results. A M S subject classification: Primary 34D, Secondary 93D.


The Inverse Nonstationary Scattering Problem For A Hyperbolic System Of Equations On Semi-Axis, N. Sh. Iskenderov, A. Yildiz Jan 1996

The Inverse Nonstationary Scattering Problem For A Hyperbolic System Of Equations On Semi-Axis, N. Sh. Iskenderov, A. Yildiz

Turkish Journal of Mathematics

In this paper, the direct and inverse nonstationary scattering problem for a hyperbolic system of n equations (n>3) on a semi-axis is studied. The coefficients of the system are uniquely determined according to scattering operator. The solution of the problem is generalized for an arbitrary natural number n applying the properties of separation of factors by means of operator transformations to some elements of the scattering operator and its inverse as well as reducing the scattering problem given on a semi-axis to the scattering problem on the whole-axis.


Some Applications Of Fractional Calculus Operators To A Certain Subclass Of Analytic Functions With Negative Coefficients, Nak Eun Cho, M. K. Aouf Jan 1996

Some Applications Of Fractional Calculus Operators To A Certain Subclass Of Analytic Functions With Negative Coefficients, Nak Eun Cho, M. K. Aouf

Turkish Journal of Mathematics

The object of the present paper is to prove various distortion theorems for the fractional calculus of functions in the class T_{n}\left(\lambda,\alpha\right) consisting of analytic and univalent functions with negative coefficients. Furthermore, a distortion theorem for a fractional integral operator of functions in the class T_{n}\left(\lambda,\alpha\right) is shown.


On A Differential Sequence In Geometry, E. Ortaçgi̇l Jan 1996

On A Differential Sequence In Geometry, E. Ortaçgi̇l

Turkish Journal of Mathematics

We construct an exact differential sequence which indicates certain relations between curvature, local flatness, torsion and simplicity of higher order connections. Our formulas are expressed explicity in terms of the Christoffel symbols of dual \varepsilon-connections.


On The \Ell_{P} Norms Of Almost Cauchy-Toeplitz Matrices, D. Bozkurt Jan 1996

On The \Ell_{P} Norms Of Almost Cauchy-Toeplitz Matrices, D. Bozkurt

Turkish Journal of Mathematics

In this study, we have given the definition of almost Cauchy-Toeplitz matrix. i.e. its elements are t_{ij}= a(i=j) and t_{ij}=1/(i-j)\, (i\neq j) such that a is a real number. We have found a lower and upper bounds for the \ell_{p} norm of this matrix. Furthermore, we have done the proof of the conjecture that were given by myself for the spectral norm of this matrix.


On (\Sigma,\Tau) Derivations With Module Values, M. Soytürk Jan 1996

On (\Sigma,\Tau) Derivations With Module Values, M. Soytürk

Turkish Journal of Mathematics

Let R be a ring, X\neq (0) an R-bi-module, d: R\ra X a(\sigma,\tau)- derivation with module value such that d\sigma=\sigma d, d\tau=\tau d and U\neq (0) an ideal of R. Furthermore the following properties are also satisfied. \begin{eqnarray*} && \mbox{For }x\in X, a\in R\quad x Ra=0 \mbox{ implies } x=0 \mbox{ or } a=0 \ldots\ldots (G_{1})\\ && \mbox{For }a\in R, x\in X \quad a Rx=0 \mbox{ implies } a=0 \mbox{ or } x=0 \ldots\ldots (G_{2}) \end{eqnarray*} \noindent In this paper we have proved the following results; (1) If (G_{1}) (or (G_{2})) is satisfied and for a \in R, d(U) a=0 …