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Oscillation Criteria For Second Order Nonlinear Differential Equations With Damping, Aydin Ti̇ryaki̇, Ağacik Zafer Jan 2000

Oscillation Criteria For Second Order Nonlinear Differential Equations With Damping, Aydin Ti̇ryaki̇, Ağacik Zafer

Turkish Journal of Mathematics

Oscillation criteria are given for second order nonlinear differential equations with damping of the form $$(a(t) \psi (x ) \dot x)\dot{}+ p(t) \dot x + q (t) f (x ) = 0,\quad t\geq t_0,$$ where $p$ and $q$ are allowed to change signs on $[t_0,\infty)$. We employ the averaging technique to obtain sufficient conditions for oscillation of solutions of the above equation. Our results generalize and extend some known oscillation criteria in the literature.


Some Graph Type Hypersurfaces In A Semi-Euclidean Space, Ikawa Toshihiko, Honda Kyoko Jan 2000

Some Graph Type Hypersurfaces In A Semi-Euclidean Space, Ikawa Toshihiko, Honda Kyoko

Turkish Journal of Mathematics

We consider some graph type hypersurfaces in a semi-Euclidean space $\Bbb R^{n+1}_{q}$ and give conditions of the dimension $n+1$ and the index $q$ when a hypersurface is lightlike, totally geodesic and minimal.


Conjugacy Classes Of Elliptic Elements In The Picard Group, Ni̇hal Yilmaz, İsmai̇l Naci̇ Cangül Jan 2000

Conjugacy Classes Of Elliptic Elements In The Picard Group, Ni̇hal Yilmaz, İsmai̇l Naci̇ Cangül

Turkish Journal of Mathematics

The Picard group $\mathbf{P}$ is a discrete subgroup of $PSL(2,\Bbb{C})$ with Gaussian integer coefficients. Here it is shown that the total number of conjugacy classes of elliptic elements of order 2 and 3 in $\mathbf{P}$, which is given as seven by B. Fine $\left[ 3\right] $, can actually be reduced to four and using this, the conditions for the maximal Fuchsian subgroups of $\mathbf{P}$ to have elliptic elements of orders 2 and 3 are found.


Cover And Contents Jan 2000

Cover And Contents

Turkish Journal of Mathematics

No abstract provided.


The K-Derivation Of A Gamma-Ring, Hati̇ce Kandamar Jan 2000

The K-Derivation Of A Gamma-Ring, Hati̇ce Kandamar

Turkish Journal of Mathematics

In this paper, the $k$-derivation is defined on a $\Gamma$-ring $M$ (that is, if $M$ is a $\Gamma$-ring, $d:M\to M$ and $k:\Gamma\to \Gamma$ are to additive maps such that $d(a\beta b )= d(a)\beta b + ak(\beta)b + a\beta d(b) $ for all $a,b\in M, \quad \beta \in \Gamma$, then $d$ is called a $k$-derivation of $M$) and the following results are proved. (1) Let $R$ be a ring of characteristic not equal to 2 such that if $xry=0$ for all $x, y\in R$ then $r=0$. If $d$ is a $k$-derivation of the $(R=)\Gamma$-ring $R$ with $k=d$, then $d$ is the …


Strongly Prime Ideals In Cs-Rings, Gonca Güngöroğlu Jan 2000

Strongly Prime Ideals In Cs-Rings, Gonca Güngöroğlu

Turkish Journal of Mathematics

We study and characterize strongly prime right ideals in CS-rings.


Qr-Submanifolds And Almost Contact 3-Structure, Rifat Güneş, Bayram Şahi̇n, Sadik Keleş Jan 2000

Qr-Submanifolds And Almost Contact 3-Structure, Rifat Güneş, Bayram Şahi̇n, Sadik Keleş

Turkish Journal of Mathematics

In this paper,QR-submanifolds of quaternion Kaehlerian manifolds with $\dim \nu ^{\perp }=1$ has been considered. It is shown that each QR-submanifold of quaternion Kaehlerian manifold with $\dim \nu ^{\perp }=1$ is a manifold with an almost contact 3-structure. We apply geometric theory of almost contact 3-structure to the classification of QR-submanifolds (resp.Real hypersurfaces) of quaternion Kaehler manifolds (resp.$IR^{4m}$, $m>1$). Some results on integrability of an invariant distribution of a QR-submanifold and on the immersions of its leaves are also obtained.


On Non-Homogeneous Riemann Boundary Value Problem, Kadi̇r Kutlu Jan 2000

On Non-Homogeneous Riemann Boundary Value Problem, Kadi̇r Kutlu

Turkish Journal of Mathematics

In this paper we consider non-homogeneous Riemann boundary value problem with unbounded oscillating coefficients on a class of open rectifiable Jordan curve.


Lifts Of Derivations To The Semitangent Bundle, Ari̇f A. Salimov, Ekrem Kadioğlu Jan 2000

Lifts Of Derivations To The Semitangent Bundle, Ari̇f A. Salimov, Ekrem Kadioğlu

Turkish Journal of Mathematics

The main purpose of this paper is to investigate the complete lifts of derivations for semitangent bundle and to discuss relations between these and lifts already known.


On Characterization Of Metric Completeness, Guo-Jing Jiang Jan 2000

On Characterization Of Metric Completeness, Guo-Jing Jiang

Turkish Journal of Mathematics

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


On Torsion-Free Barely Transitive Groups, Mahmut Kuzucuoğlu Jan 2000

On Torsion-Free Barely Transitive Groups, Mahmut Kuzucuoğlu

Turkish Journal of Mathematics

B. Hartley asked the following question: Does there exist a torsion free barely transitive group? Existence of torsion free simple barely transitive group is also unknown. We answer the latter question negatively in a special case. Moreover we proved the following: Let $G$ be a simple barely transitive group, and $H$ be a stabilizer of a point. If for a non-identity element $x \in G$, $C_G (x)$ is infinite then, $C_G (x)$ cannot contain $H$.


A Remark On The Asymptotic Properties Of Positive Homogeneous Maps On Homogeneous Lattices, Alp Eden Jan 2000

A Remark On The Asymptotic Properties Of Positive Homogeneous Maps On Homogeneous Lattices, Alp Eden

Turkish Journal of Mathematics

An abstract version of Lyapunov exponents is defined for positive homogeneous maps on Homogeneous Lattices and a sufficient condition is given for the asymptotic stability of the map.


Intrinsic Equations For A Relaxed Elastic Line On An Oriented Hypersurface In The Minkowski Space R^N_1, Nevi̇n Gürbüz, Ali̇ Görgülü Jan 2000

Intrinsic Equations For A Relaxed Elastic Line On An Oriented Hypersurface In The Minkowski Space R^N_1, Nevi̇n Gürbüz, Ali̇ Görgülü

Turkish Journal of Mathematics

We gived the intrinsic equations for a relaxed elastic line on an oriented surface in ${\Bbb {R}}_1^3$ ([1],[2]). In this paper, we derived the intrinsic equations for a relaxed elastic line on an oriented time-like hypersurface and space-like hypersurface in the Minkowski space ${\Bbb {R}}_1^n$ and gived additional results about relaxed elastic lines on various timelike and spacelike hypersurface in the Minkowski space ${\Bbb {R}}_1^n$.


On Generalized Higher Derivations, Atsushi Nakajima Jan 2000

On Generalized Higher Derivations, Atsushi Nakajima

Turkish Journal of Mathematics

We define the notion of generalized higher derivations and give some elementary relations between generalized higher derivations and higher derivations in the usual sense. We extend the result of an exact sequence of the set of all derivations $\text{Der}(A, M)$ and the set of all generalized derivations $g\text{Der}(A, M)$ given in [N1, Theorem 2.4]. Moreover, we discuss generalized higher Jordan derivations and Lie derivations.


Multipliers Between Orlicz Sequence Spaces, P. B. Djakov, M. S. Ramanuan Jan 2000

Multipliers Between Orlicz Sequence Spaces, P. B. Djakov, M. S. Ramanuan

Turkish Journal of Mathematics

Let $M, N $ be Orlicz functions, and let $D(\ell_M , \ell_N ) $ be the space of all diagonal operators (that is multipliers) acting between the Orlicz sequence spaces $\ell_M$ and $\ell_N$. We prove that the space of multipliers $D(\ell_M , \ell_N )$ coincides with (and is isomorphic to) the Orlicz sequence space $ \ell_{M_N^{*}} ,$ where $ M_N^{*} $ is the Orlicz function defined by $M_N^{*}(\lambda ) = \sup \{ N(\lambda x) - M(x), \; x \in (0,1) \}$.


Cover And Contents Jan 2000

Cover And Contents

Turkish Journal of Mathematics

No abstract provided.


The Pitch And The Angle Of Pitch Of A Closed Nonnull Ruled Hypersurface Whose Generator Is Spacelike In R^{K+2}_1, Ayşe Altin, Aysel Turgut Vanli Jan 2000

The Pitch And The Angle Of Pitch Of A Closed Nonnull Ruled Hypersurface Whose Generator Is Spacelike In R^{K+2}_1, Ayşe Altin, Aysel Turgut Vanli

Turkish Journal of Mathematics

In this paper, the pitch and the angle of pitch of a closed nonnull ruled hypersurface whose generators are spacelike are calculated in $R^{k+2}_1 $.


A Borsuk-Ulak Theorem For Heisenberg Group Actions, Necdet Güner Jan 2000

A Borsuk-Ulak Theorem For Heisenberg Group Actions, Necdet Güner

Turkish Journal of Mathematics

Let $G=H_{2n+1}$ be a $(2n+1)$-dimensional Heisenberg Lie group acts on $M=C^m-\{0\}$ and $M^{'}=C^{m'}-\{0\}$ exponentially. By using Cohomological Index we proved the following theorem. If $f:M{\to}M^{'}$ is a $G$-equivariant map, then $m{\le}m'$.


On Conjugation In The Mod-P Steenrod Algebra, İsmet Karaca, İlkay Yaslan Karaca Jan 2000

On Conjugation In The Mod-P Steenrod Algebra, İsmet Karaca, İlkay Yaslan Karaca

Turkish Journal of Mathematics

In this paper we prove a formula involving the canonical anti-automorphism $\chi$ of the mod-$p$ Steenrod algebra.


On The Linearity Of Certain Mapping Class Groups, Mustafa Korkmaz Jan 2000

On The Linearity Of Certain Mapping Class Groups, Mustafa Korkmaz

Turkish Journal of Mathematics

S. Bigelow proved that the braid groups are linear. That is, there is a faithful representation of the braid group into the general linear group of some field. Using this, we deduce from previously known results that the mapping class group of a sphere with punctures and hyperelliptic mapping class groups are linear. In particular, the mapping class group of a closed orientable surface of genus $2$ is linear.


On Subspaces Isomorphic To L^Q In Interpolation Of Quasi Banach Spaces, J. A. Lopez Molina Jan 2000

On Subspaces Isomorphic To L^Q In Interpolation Of Quasi Banach Spaces, J. A. Lopez Molina

Turkish Journal of Mathematics

We show that every sequence $\{x_n\}_{n=1}^{\infty}$ in a real interpolation space $(E_0,E_1)_{\theta,q}$, $0 < \theta < 1$, $0 < q < \infty,$ of quasi Banach spaces $E_0,E_1,$ which is $0-$convergent in $E_0 + E_1$ but $\inf_n \;\ x_n\ _{(E_0,E_1)_{\theta,q}} > 0,$ has a subsequence which is equivalent to the standard unit basis of $\ell^q.$


The P-Stirling Numbers, Russel Merris Jan 2000

The P-Stirling Numbers, Russel Merris

Turkish Journal of Mathematics

The purpose of this article is to introduce \( p \)-Stirling numbers of the first and second kinds.


Some Radius Problem For Certain Families Of Analytic Functions, Yaşar Polatoğlu, Meti̇n Bolcal Jan 2000

Some Radius Problem For Certain Families Of Analytic Functions, Yaşar Polatoğlu, Meti̇n Bolcal

Turkish Journal of Mathematics

The aim of this paper is to give bounds of the radius of $\alpha $-convexity for certain families of analytic functions in the unit disc. The radius of $\alpha $-convexity is generalization of the radius of convexity and the radius of starlikeness, and introduced by S.S.Miller; P.T.Mocanu and M.O.Reade [3,4]


New And Old Types Of Homogeneity, Ali̇ Ahmad Fora Jan 2000

New And Old Types Of Homogeneity, Ali̇ Ahmad Fora

Turkish Journal of Mathematics

We introduce new types of homogeneity ; namely : locally homogeneity and closed homogeneity .Several results are included discussing some relations between these types and the old ones. Some characterization and decomposition theorems are obtained. Relevant examples and counterexamples are discussed throughout this paper.


Cover And Contents Jan 2000

Cover And Contents

Turkish Journal of Mathematics

No abstract provided.


An Autecological Study On Iris Histrioides Foster (Iridaceae) Distributed In The Central Black Sea Region, Nezahat Kandemi̇r, Ali̇ Engi̇n Jan 2000

An Autecological Study On Iris Histrioides Foster (Iridaceae) Distributed In The Central Black Sea Region, Nezahat Kandemi̇r, Ali̇ Engi̇n

Turkish Journal of Botany

Iris histrioides Foster, a Euxinian and endemic element, was investigated in terms of its phenological and ecological properties. Some elements taken from the above-and below-ground parts of the plant in the vegetative and generative growth periods have been analyzed. According to the results of the analysis, N%,P% and K% contets are high in above-ground parts during the vegetative growth phase. In addition, soil samples were collected from 0-20 cm depth and analyzed physically and chemically.


Seasonal Changes In The Phytoplankton Of The Northeastern Mediterranean(Bay Of Iskenderun), Sevi̇m Polat, Ercan Sarihan, Tufan Koray Jan 2000

Seasonal Changes In The Phytoplankton Of The Northeastern Mediterranean(Bay Of Iskenderun), Sevi̇m Polat, Ercan Sarihan, Tufan Koray

Turkish Journal of Botany

This study was carried out in the northern part of the Bay of Iskenderun in the northeastern Mediterranean during the period 1994-1995. The quantitative and qualitative distribution of phytoplankton, the environmental factors that affect its distribution and the changes in succession over time were investigated. At each of the seven stations, monthly sampling was done from the surface and 10.0 m depth. In spring, the sampling was performed once every two weeks. In addition, the measurements of some physical and chemical parameters i.e. temperature, salinity, (NO^-_3 +NO^-_2 )-N and PO4^-_3 -P were carried out. At the end of the study, …


Taxonomic And Paelogeographic Approaches To The Dasyclad Algae In The Upper Jurassic (Kimmeridgian)-Upper Cretaceous (Cenomanian) Peritidal Carbonates Of The Fele (Yassıbel) Area (Western Taurides, Turkey), İsmai̇l Ömer Yilmaz Jan 1999

Taxonomic And Paelogeographic Approaches To The Dasyclad Algae In The Upper Jurassic (Kimmeridgian)-Upper Cretaceous (Cenomanian) Peritidal Carbonates Of The Fele (Yassıbel) Area (Western Taurides, Turkey), İsmai̇l Ömer Yilmaz

Turkish Journal of Earth Sciences

In the Fele (Yassıbel) area in the north of Beyşehir Lake in the Western Taurides, Upper Jurassic (Kimmeridgian) - Upper Cretaceous (Cenomanian) peritidal carbonates were studied in detail. In this study, 30 species of dasyclad algae were identified and 3 new Salpingoporella species were identified within the peritidal carbonates. It was determined that they belong to 13 different genera: Acroporella, Actinoporella, Campbelliella, Clypeina, Cylindroporella, Epimastopora, Epimastoporella, Kopetdagaria, Macroporella, Otternstella, Rajkaella, Salpingoporella, and Selliporella. Salpingoporella is the dominant genus. Some of the species are new records for Turkey: Clypeina nigra, Clypeina parasolkani, Otternstella lemmensis, Salpingoporella biokovensis, Salpingoporella circassa, Salpingoporella piriniae, and …


Clinopyroxene Compositions Of The Isotropic Gabbros From The Sarıkaraman Ophiolite: New Evidence On Supra-Subduction Zone Type Magma Genesis In Central Anatolia, Kenan M. Yaliniz, M. Cemal Göncüoğlu Jan 1999

Clinopyroxene Compositions Of The Isotropic Gabbros From The Sarıkaraman Ophiolite: New Evidence On Supra-Subduction Zone Type Magma Genesis In Central Anatolia, Kenan M. Yaliniz, M. Cemal Göncüoğlu

Turkish Journal of Earth Sciences

The Sarıkaraman Ophiolite is one of the least dismembered ophiolitic units of the allochthonous Central Anatolian Ophiolites, which retains its recognizable pseudostratigraphy. The Sarıkaraman Ophiolite is represented in its lowermost part by isotropic gabbros. Within the isotropic gabbro sequence, clinopyroxenes are observed as small, colorless relicts with a cloudy appearance. In most of the samples, they are completely replaced by a successive generation of green to brown amphiboles. Clinopyroxenes display diopsitic to augitic compositions within the range of En 45 Fs 5 Wo 49 to En 50 Fs 9 Wo 41 . They are Ca-rich and Na-poor (Na 2 O


Field, Petrographic And Geochemical Features Of The Baranadağ Quartz Monzonite Of The Central Anatolian Granitoids, Turkey, Nurdan S. Aydin, A. Piril Önen Jan 1999

Field, Petrographic And Geochemical Features Of The Baranadağ Quartz Monzonite Of The Central Anatolian Granitoids, Turkey, Nurdan S. Aydin, A. Piril Önen

Turkish Journal of Earth Sciences

The Baranadağ quartz monzonite is one of the granitioid intrusions of the Central Anatolian Crystalline Complex (CACC) which represents the passive continental margin of the Anatolide-Tauride platform. Medium to coarse-grained Baranadağ quartz monzonites typically include mafic microgranular enclaves and K-feldspar megacrysts and are cut by aplitic dykes representing the youngest magmatic activity of the study area. The intrusion is mainly composed of orthoclase, plagioclase, quartz, hornblende, biotite and clinopyroxene. It displays a slightly alkaline character and relatively well-developed calc-alkaline trend. The metaluminous Baranadağ quartz monzonites show comparable field, petrographic and/or geochemical features with those of the H-type (Hybrid) granitoids of …