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2010

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Articles 511 - 540 of 690

Full-Text Articles in Mathematics

On Purely Real Surfaces In Kaehler Surfaces, Bang-Yen Chen Jan 2010

On Purely Real Surfaces In Kaehler Surfaces, Bang-Yen Chen

Turkish Journal of Mathematics

An immersion \phi colon M to \tilde M^2 of a surface M into a Kaehler surface is called purely real if the complex structure J on \tilde M^2 carries the tangent bundle of M into a transversal bundle. In the first part of this article, we prove that the equation of Ricci is a consequence of the equations of Gauss and Codazzi for purely real surfaces in any Kaehler surface. In the second part, we obtain a necessary condition for a purely real surface in a complex space form to be minimal. Several applications of this condition are provided. In …

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When \Delta-Semiperfect Rings Are Semiperfect, Engi̇n Büyükaşik, Christian Lomp Jan 2010

When \Delta-Semiperfect Rings Are Semiperfect, Engi̇n Büyükaşik, Christian Lomp

Turkish Journal of Mathematics

Zhou defined \delta-semiperfect rings as a proper generalization of semiperfect rings. The purpose of this paper is to discuss relative notions of supplemented modules and to show that the semiperfect rings are precisely the semilocal rings which are \delta-supplemented. Module theoretic version of our results are obtained.

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Generalized Fibonacci Sequences Related To The Extended Hecke Groups And An Application To The Extended Modular Group, Özden Koruoğlu, Recep Şahi̇n Jan 2010

Generalized Fibonacci Sequences Related To The Extended Hecke Groups And An Application To The Extended Modular Group, Özden Koruoğlu, Recep Şahi̇n

Turkish Journal of Mathematics

The extended Hecke groups \overline{H}(\lambda _{q}) are generated by T(z)=-1/z, S(z)=-1/(z+\lambda _{q}) and R(z)=1/ \overline{z} with \lambda _{q}=2\cos (\pi /q) for q\geq 3 integer. In this paper, we obtain a sequence which is a generalized version of the Fibonacci sequence given in [6] for the extended modular group \overline{\Gamma }, in the extended Hecke groups \overline{H}(\lambda_{q}). Then we apply our results to \overline{\Gamma } to find all elements of the extended modular group \overline{\Gamma }.

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Some Sufficient Conditions For Starlikeness And Convexity, Mamoru Nunokawa, Shigeyoshi Owa, Yaşar Polatoğlu, Mert Çağlar, Emel Yavuz Duman Jan 2010

Some Sufficient Conditions For Starlikeness And Convexity, Mamoru Nunokawa, Shigeyoshi Owa, Yaşar Polatoğlu, Mert Çağlar, Emel Yavuz Duman

Turkish Journal of Mathematics

There are many results for sufficient conditions of functions f(z) which are analytic in the open unit disc U to be starlike and convex in U. In view of the results due to S. Ozaki, I. Ono and T. Umezawa (1956), P.T. Mocanu (1988), and M. Nunokawa (1993), some sufficient conditions for starlikeness and convexity of f(z) are discussed.

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Injective Simplicial Maps Of The Arc Complex, Elmas Irmak, John D. Mccarthy Jan 2010

Injective Simplicial Maps Of The Arc Complex, Elmas Irmak, John D. Mccarthy

Turkish Journal of Mathematics

In this paper, we prove that each injective simplicial map of the arc complex of a compact, connected, orientable surface with nonempty boundary is induced by a homeomorphism of the surface. We deduce, from this result, that the group of automorphisms of the arc complex is naturally isomorphic to the extended mapping class group of the surface, provided the surface is not a disc, an annulus, a pair of pants, or a torus with one hole. We also show, for each of these special exceptions, that the group of automorphisms of the arc complex is naturally isomorphic to the quotient …

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An Expansion Result For A Sturm-Liouville Eigenvalue Problem With Impulse, Şeri̇fe Faydaoğlu, Gusein Sh. Guseinov Jan 2010

An Expansion Result For A Sturm-Liouville Eigenvalue Problem With Impulse, Şeri̇fe Faydaoğlu, Gusein Sh. Guseinov

Turkish Journal of Mathematics

The paper is concerned with an eigenvalue problem for second order differential equations with impulse. Such a problem arises when the method of separation of variables applies to the heat conduction equation for two-layered composite. The existence of a countably infinite set of eigenvalues and eigenfunctions is proved and a uniformly convergent expansion formula in the eigenfunctions is established.

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On The Qualitative Analysis Of The Uniqueness Of The Movement Of Endothelial Cells, Erdem Altuntaç, Serdal Pamuk Jan 2010

On The Qualitative Analysis Of The Uniqueness Of The Movement Of Endothelial Cells, Erdem Altuntaç, Serdal Pamuk

Turkish Journal of Mathematics

This paper extends the work of Pamuk (2003) by showing mathematically that the movement of endothelial cells, to the regions where active enzyme is large or where fibronectin is small, is unique. To do this, we obtain the existence and uniqueness of the steady-state solution of an initial-boundary value problem which mathematically models endothelial cell movement in tumor angiogenesis. A specific example showing the instability of this steady-state solution is provided.

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Some Properties Of C-Fusion Frames, Mohammad Hasan Faroughi, Reza Ahmadi Jan 2010

Some Properties Of C-Fusion Frames, Mohammad Hasan Faroughi, Reza Ahmadi

Turkish Journal of Mathematics

In [10], we generalized the concept of fusion frames, namely, c-fusion frames, which is a continuous version of the fusion frames. In this article we give some important properties about the generalization, namely erasures of subspaces, the bound of c-erasure reconstruction error for Parseval c-fusion frames, perturbation of c-fusion frames and the frame operator for fusion pair.

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A Short Survey On Mathematical Work Of Cemal Koç, İsmai̇l Şuayi̇p Güloğlu Jan 2010

A Short Survey On Mathematical Work Of Cemal Koç, İsmai̇l Şuayi̇p Güloğlu

Turkish Journal of Mathematics

No abstract provided.

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Generalized Catalan Numbers, Sequences And Polynomials, Cemal Koç, İsmai̇l Güloğlu, Songül Esi̇n Jan 2010

Generalized Catalan Numbers, Sequences And Polynomials, Cemal Koç, İsmai̇l Güloğlu, Songül Esi̇n

Turkish Journal of Mathematics

In this paper we present an algebraic interpretation for generalized Catalan numbers. We describe them as dimensions of certain subspaces of multilinear polynomials. This description is of utmost importance in the investigation of annihilators in exterior algebras.

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Swan Conductors And Torsion In The Logarithmic De Rham Complex, Si̇nan Ünver Jan 2010

Swan Conductors And Torsion In The Logarithmic De Rham Complex, Si̇nan Ünver

Turkish Journal of Mathematics

We prove, for an arithmetic scheme X/S over a discrete valuation ring whose special fiber is a strict normal crossings divisor in X, that the Swan conductor of X/S is equal to the Euler characteristic of the torsion in the logarithmic de Rham complex of X/S. This is a precise logarithmic analog of a theorem by Bloch [1].

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On Abelian Rings, Nazim Agayev, Abdullah Harmanci, Sai̇t Halicioğlu Jan 2010

On Abelian Rings, Nazim Agayev, Abdullah Harmanci, Sai̇t Halicioğlu

Turkish Journal of Mathematics

Let \alpha be an endomorphism of an arbitrary ring R with identity. In this note, we introduce the notion of \alpha-abelian rings which generalizes abelian rings. We prove that \alpha-reduced rings, \alpha-symmetric rings, \alpha-semicommutative rings and \alpha-Armendariz rings are \alpha-abelian. For a right principally projective ring R, we also prove that R is \alpha-reduced if and only if R is \alpha-symmetric if and only if R is \alpha-semicommutative if and only if R is \alpha-Armendariz if and only if R is \alpha-Armendariz of power series type if and only if R is \alpha-abelian.

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Pseudo Simplicial Groups And Crossed Modules, İlker Akça, Sedat Pak Jan 2010

Pseudo Simplicial Groups And Crossed Modules, İlker Akça, Sedat Pak

Turkish Journal of Mathematics

In this paper, we define the notion of pseudo 2-crossed module and give a relation between the pseudo 2-crossed modules and pseudo simplicial groups with Moore complex of length 2.

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On Construction Of Coherent States Associated With Homogeneous Spaces, Ali Akbar Arefijamaal Jan 2010

On Construction Of Coherent States Associated With Homogeneous Spaces, Ali Akbar Arefijamaal

Turkish Journal of Mathematics

In this article, assume that G=H\times_{\tau} K is the semidirect product of two locally compact groups H and K, respectively and consider the quasi regular representation on G. Then for some closed subgroups of G we investigate an admissible condition to generate the Gilmore-Perelomov coherent states. The construction yields a wide variety of coherent states, labelled by a homogeneous space of G.

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Order-Isomorphism And A Projection's Diagram Of C(X), Ahmed S. Al-Rawashdeh, Sultan M. Al-Suleiman Jan 2010

Order-Isomorphism And A Projection's Diagram Of C(X), Ahmed S. Al-Rawashdeh, Sultan M. Al-Suleiman

Turkish Journal of Mathematics

A mapping between projections of C^*-algebras preserving the orthogonality, is called an orthoisomorphism. We define the order-isomorphism mapping on C^*-algebras, and using Dye's result, we prove in the case of commutative unital C^*-algebras that the concepts; order-isomorphism and the orthoisomorphism coincide. Also, we define the equipotence relation on the projections of C(X); indeed, new concepts of finiteness are introduced. The classes of projections are represented by constructing a special diagram, we study the relation between the diagram and the topological space X. We prove that an order-isomorphism, which preserves the equipotence of projections, induces a diagram-isomorphism; also if two diagrams …

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The Essential Norm Of A Composition Operator On Orlicz Spaces, M. R. Jabbarzadeh Jan 2010

The Essential Norm Of A Composition Operator On Orlicz Spaces, M. R. Jabbarzadeh

Turkish Journal of Mathematics

In this note we determine the lower and upper estimates for the essential norm of a composition operator on the Orlicz spaces under certain conditions.

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Complete Systems Of Differential Invariants Of Vector Fields In A Euclidean Space, Djavvat Khadjiev Jan 2010

Complete Systems Of Differential Invariants Of Vector Fields In A Euclidean Space, Djavvat Khadjiev

Turkish Journal of Mathematics

The system of generators of the differential field of all G-invariant differential rational functions of a vector field in the n-dimensional Euclidean space R^n is described for groups G=M(n) and G=SM(n), where M(n) is the group of all isometries of R^n and SM(n) is the group of all euclidean motions of R^n. Using these results, vector field analogues of the first part of the Bonnet theorem for groups Aff(n), M(n), SM(n) in R^n are obtained, where Aff(n) is the group of all affine transformations of R^n. These analogues are given in terms of the first fundamental form and Christoffel symbols …

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Number Of Pseudo--Anosov Elements In The Mapping Class Group Of A Four--Holed Sphere, Feri̇he Atalan, Mustafa Korkmaz Jan 2010

Number Of Pseudo--Anosov Elements In The Mapping Class Group Of A Four--Holed Sphere, Feri̇he Atalan, Mustafa Korkmaz

Turkish Journal of Mathematics

We compute the growth series and the growth functions of reducible and pseudo-Anosov elements of the pure mapping class group of the sphere with four holes with respect to a certain generating set. We prove that the ratio of the number of pseudo-Anosov elements to that of all elements in a ball with center at the identity tends to one as the radius of the ball tends to infinity.

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Bicircular Matroids With Circuits Of At Most Two Sizes, Torina Deachune Lewis Jan 2010

Bicircular Matroids With Circuits Of At Most Two Sizes, Torina Deachune Lewis

Electronic Theses and Dissertations

Young in his paper titled, Matroid Designs in 1973, reports that Murty in his paper titled, Equicardinal Matroids and Finite Geometries in 1968, was the first to study matroids with all hyperplanes having the same size. Murty called such a matroid an ``Equicardinal Matroid''. Young renamed such a matroid a ``Matroid Design''. Further work on determining properties of these matroids was done by Edmonds, Murty, and Young in their papers published in 1972, 1973, and 1970 respectively. These authors were able to connect the problem of determining the matroid designs with specified parameters with results on balanced incomplete block designs. …

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Morphing Of Triangular Meshes In Shape Space, Stefanie Wuhrer, Prosenjit Bose, Chang Shu, Joseph O'Rourke, Alan Brunton Jan 2010

Morphing Of Triangular Meshes In Shape Space, Stefanie Wuhrer, Prosenjit Bose, Chang Shu, Joseph O'Rourke, Alan Brunton

Computer Science: Faculty Publications

We present a novel approach to morph between two isometric poses of the same non-rigid object given as triangular meshes. We model the morphs as linear interpolations in a suitable shape space S. For triangulated 3D polygons, we prove that interpolating linearly in this shape space corresponds to the most isometric morph in R3 . We then extend this shape space to arbitrary triangulations in 3D using a heuristic approach and show the practical use of the approach using experiments. Furthermore, we discuss a modified shape space that is useful for isometric skeleton morphing. All of the newly presented …

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Spatial Isomorphisms Of Algebras Of Truncated Toeplitz Operators, William T. Ross, Stephan Ramon Garcia, Warren R. Wogen Jan 2010

Spatial Isomorphisms Of Algebras Of Truncated Toeplitz Operators, William T. Ross, Stephan Ramon Garcia, Warren R. Wogen

Department of Math & Statistics Faculty Publications

We examine when two maximal abelian algebras in the truncated Toeplitz operators are spatially isomorphic. This builds upon recent work of N. Sedlock, who obtained a complete description of the maximal algebras of truncated Toeplitz operators.

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The Norm Of A Truncated Toeplitz Operator, William T. Ross, Stephan Ramon Garcia Jan 2010

The Norm Of A Truncated Toeplitz Operator, William T. Ross, Stephan Ramon Garcia

Department of Math & Statistics Faculty Publications

We prove several lower bounds for the norm of a truncated Toeplitz operator and obtain a curious relationship between the H2 and H∞ norms of functions in model spaces.

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Digraphs With Isomorphic Underlying And Domination Graphs: 4-Cycles And Pairs Of Paths, Kim A. S. Factor, Larry J. Langley Jan 2010

Digraphs With Isomorphic Underlying And Domination Graphs: 4-Cycles And Pairs Of Paths, Kim A. S. Factor, Larry J. Langley

Mathematics, Statistics and Computer Science Faculty Research and Publications

A domination graph of a digraph D, dom(D), is created using the vertex set of D, V(D). There is an edge uv in dom(D) whenever (u, z) or (v, z) is in the arc set of D, A(D), for every other vertex z ε V(D). For only some digraphs D has the structure of dom(D) been characterized. Examples of this are tournaments and regular digraphs. The authors have characterizations for the structure of digraphs D for …

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A Mobile Intelligent Interruption Management System, Sina Zulkernain, Praveen Madiraju, Sheikh Iqbal Ahamed, Karl Stamm Jan 2010

A Mobile Intelligent Interruption Management System, Sina Zulkernain, Praveen Madiraju, Sheikh Iqbal Ahamed, Karl Stamm

Mathematics, Statistics and Computer Science Faculty Research and Publications

Mobile phones have become the most hated device that people cannot live without. For its primary usage as a communication device, it has surpassed any other medium. But it comes with a high price, interruption, anywhere anytime. These unwanted interruptions cause loss of productivity and also mostly not beneficial to the immediate task at hand, and moving them few minutes into the future can increase productivity. Considering receiver’s unavailability, it is possible to manage cell phone disruptions using advanced features like sensing capability, ubiquitous computing and context aware systems. This paper proposes the architecture of a system named Mobile Intelligent …

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Local Out-Tournaments With Upset Tournament Strong Components I: Full And Equal {0,1}-Matrix Ranks, Kim A. S. Factor, Rebecca M. Kohler, Jason M. Derby Jan 2010

Local Out-Tournaments With Upset Tournament Strong Components I: Full And Equal {0,1}-Matrix Ranks, Kim A. S. Factor, Rebecca M. Kohler, Jason M. Derby

Mathematics, Statistics and Computer Science Faculty Research and Publications

A digraph D is a local out-tournament if the outset of every vertex is a tournament. Here, we use local out-tournaments, whose strong components are upset tournaments, to explore the corresponding ranks of the adjacency matrices. Of specific interest is the out-tournament whose adjacency matrix has boolean, nonnegative integer, term, and real rank all equal to the number of vertices, n. Corresponding results for biclique covers and partitions of the digraph are provided.

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Digraphs With Isomorphic Underlying And Domination Graphs: Pairs Of Paths, Kim A. S. Factor, Larry J. Langley Jan 2010

Digraphs With Isomorphic Underlying And Domination Graphs: Pairs Of Paths, Kim A. S. Factor, Larry J. Langley

Mathematics, Statistics and Computer Science Faculty Research and Publications

A domination graph of a digraph D, dom (D), is created using thc vertex set of D and edge uv ϵ E (dom (D)) whenever (u, z) ϵ A (D) or (v, z) ϵ A (D) for any other vertex z ϵ A (D). Here, we consider directed graphs whose underlying graphs are isomorphic to their domination graphs. Specifically, digraphs are completely characterized where UGc (D) is the union of two disjoint paths.

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Lower Semimodular Inverse Semigroups, Ii, Peter R. Jones, Kyeong Hee Cheong Jan 2010

Lower Semimodular Inverse Semigroups, Ii, Peter R. Jones, Kyeong Hee Cheong

Mathematics, Statistics and Computer Science Faculty Research and Publications

The authors’ description of the inverse semigroups S for which the lattice ℒℱ(S) of full inverse subsemigroups is lower semimodular is used to describe those for which (a) the lattice ℒ(S) of all inverse subsemigroups or (b) the lattice �o(S) of convex inverse subsemigroups has that property. In each case, we show that this occurs if and only if the entire lattice is a subdirect product of ℒℱ(S) with ℒ(E S ), or �o(E S ), respectively, where E S is the semilattice of idempotents of …

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Not Every Co-Existential Map Is Confluent, Paul Bankston Jan 2010

Not Every Co-Existential Map Is Confluent, Paul Bankston

Mathematics, Statistics and Computer Science Faculty Research and Publications

A continuous surjection between compacta is co-existential if it is the second of two maps whose composition is a standard ultracopower projection. Co-existential maps are always weakly confluent, and are even monotone when the range space is locally connected; so it is a natural question to ask whether they are always confluent. Here we give a negative answer. This is an interesting question, mainly because of the fact that most theorems about confluent maps have parallel versions for co-existential maps---notably, both kinds of maps preserve hereditary indecomposability. Where the known parallels break down is in the question of chainability. It …

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Truncated Toeplitz Operators: Spatial Isomorphism, Unitary Equivalence, And Similarity, William T. Ross, Joseph A. Cima, Stephan Ramon Garcia, Warren R. Wogen Jan 2010

Truncated Toeplitz Operators: Spatial Isomorphism, Unitary Equivalence, And Similarity, William T. Ross, Joseph A. Cima, Stephan Ramon Garcia, Warren R. Wogen

Department of Math & Statistics Faculty Publications

A truncated Toeplitz operator Aᵩ : KƟ → KƟ is the compression of a Toeplitz operator Tᵩ : H2 → H2 to a model space KƟ := H2 ⊖ ƟH2. For Ɵ inner, let TƟ denote the set of all bounded truncated Toeplitz operators on KƟ. Our main result is a necessary and sufficient condition on inner functions Ɵ1 and Ɵ2 which guarantees that TƟ1 and TƟ2 are spatially isomorphic. (i.e., UTƟ1 = TƟ2 U for some unitary U : KƟ1 …

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Automation Process For Morphometric Analysis Of Volumetric Ct Data From Pulmonary Vasculature In Rats, Rahul Shingrani, Gary S. Krenz, Robert Molthen Jan 2010

Automation Process For Morphometric Analysis Of Volumetric Ct Data From Pulmonary Vasculature In Rats, Rahul Shingrani, Gary S. Krenz, Robert Molthen

Mathematics, Statistics and Computer Science Faculty Research and Publications

With advances in medical imaging scanners, it has become commonplace to generate large multidimensional datasets. These datasets require tools for a rapid, thorough analysis. To address this need, we have developed an automated algorithm for morphometric analysis incorporating A Visualization Workshop computational and image processing libraries for three-dimensional segmentation, vascular tree generation and structural hierarchical ordering with a two-stage numeric optimization procedure for estimating vessel diameters. We combine this new technique with our mathematical models of pulmonary vascular morphology to quantify structural and functional attributes of lung arterial trees. Our physiological studies require repeated measurements of vascular structure to determine …

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