Essential Spectra of Quasi-parabolic Composition Operators on Hardy Spaces of the Poly-disc

This work is a generalization of the results in [Gul] to bi-disc case. As in [Gul], quasi-parabolic composition operators on the Hilbert-Hardy space of the bi-disc are written as a linear combination of Toeplitz operators and Fourier multipliers. The C*-algebra generated by Toeplitz operators and Fourier multipliers on the Hilbert-Hardy space of the bi-disc is written as the tensor product of the similar C*-algebra in one variable with itself. As a result we find a nontrivial set lying inside the essential spectra of quasi-parabolic composition operators

On the C*-algebra Generated by Toeplitz Operators and Fourier Multipliers on the Hardy Space of a Locally Compact Group

Let $G$ be a locally compact abelian Hausdorff topological group which is non-compact and whose Pontryagin dual $\Gamma$ is partially ordered. Let $\Gamma^{+}\subset\Gamma$ be the semigroup of positive elements in $\Gamma$. The Hardy space $H^{2}(G)$ is the closed subspace of $L^{2}(G)$ consisting of functions whose Fourier transforms are supported on $\Gamma^{+}$. In this paper we consider the C*-algebra $C^{*}(\mathcal{T}(G)\cup F(C(\dot{\Gamma^{+}})))$ generated by Toeplitz operators with continuous symbols on $G$ which vanish at infinity and Fourier multipliers with symbols which are continuous on one point compactification of $\Gamma^{+}$ on the Hilbert-Hardy space $H^{2}(G)$. We characterize the character space of this C*-algebra using a theorem of Power.Comment: 11 page

Determination of the perceptions of sports managers about sport concept: A metaphor analysis study

The aim of this research is to determine the perceptions of sport managers in Turkey on the concept of sport by means of metaphors. 74 sport managers participated in the research. Phenomenology, one of the qualitative research methods, was used in the research. Content analysis method was used for the data analysis. Evaluation of the data showed that sports managers produced a total of 50 metaphors. These metaphors produced were collected in 6 different categories. As a result, it was determined that sport managers expressed the concept of sport by means of metaphors in a very rich and diverse perspective. Therefore, the metaphors determined in this study may lead the sport managers and candidates responsible for the administration of sports services and activities in terms of offering a different perspective on the practice of sport management. © 2018, Sciedu Press. All rights reserved

Functional classification of G-Protein coupled receptors, based on their specific ligand coupling patterns

Functional identification of G-Protein Coupled Receptors (GPCRs) is one of the current focus areas of pharmaceutical research. Although thousands of GPCR sequences are known, many of them re- main as orphan sequences (the activating ligand is unknown). Therefore, classification methods for automated characterization of orphan GPCRs are imperative. In this study, for predicting Level 2 subfamilies of Amine GPCRs, a novel method for obtaining fixed-length feature vectors, based on the existence of activating ligand specific patterns, has been developed and utilized for a Support Vector Machine (SVM)-based classification. Exploiting the fact that there is a non-promiscuous relationship between the specific binding of GPCRs into their ligands and their functional classification, our method classifies Level 2 subfamilies of Amine GPCRs with a high predictive accuracy of 97.02% in a ten-fold cross validation test. The presented machine learning approach, bridges the gulf between the excess amount of GPCR sequence data and their poor functional characterization

An invertibility criterion in a C*-algebra acting on the Hardy space with applications to composition operators

In this paper we prove an invertibility criterion for certain operators which is given as a linear algebraic combination of Toeplitz operators and Fourier multipliers acting on the Hardy space of the unit disc. Very similar to the case of Toeplitz operators we prove that such operators are invertible if and only if they are Fredholm and their Fredholm index is zero. As an application we prove that for "quasi-parabolic" composition operators the spectra and the essential spectra are equal.Comment: 10 pages. arXiv admin note: text overlap with arXiv:1002.4640, arXiv:1205.605